Construct AYON USD environment on top launch context environment

[BigRoy]

Changelog Description

This may fix an issue where launching an application may not inherit all the needed environment variables from the launch context.

Additional info

For whatever reason I suddenly couldn't test it because I started getting issues with how the settings load in config.py

Launching tray would give me:

*** WRN: >>> { AddonsLoader }: [  FAILED to import "ayon_usd"  ]
==============================
404 Client ERROR: Not Found for url: http://localhost:5000/api/addons/ayon_usd/1.0.4-dev.37/settings?variant=2024.01.0-full-2024-01-17-02-roydev
==============================
Traceback (most recent call last):
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\ayon_api\server_api.py", line 202, in raise_for_status
    self._response.raise_for_status()
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\requests\models.py", line 1021, in raise_for_status
    raise HTTPERROR(http_ERROR_msg, response=self)
requests.exceptions.HTTPERROR: 404 Client ERROR: Not Found for url: http://localhost:5000/api/addons/ayon_usd/1.0.4-dev.37/settings?variant=2024.01.0-full-2024-01-17-02-roydev

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "E:\dev\ayon-core\client\ayon_core\addon\base.py", line 417, in _load_ayon_addons
    mod = __import__(basename, fromlist=("",))
  File "E:\dev\ayon-usd\client\ayon_usd\__init__.py", line 3, in <module>
    from .addon import USDAddon
  File "E:\dev\ayon-usd\client\ayon_usd\addon.py", line 11, in <module>
    from . import config, utils
  File "E:\dev\ayon-usd\client\ayon_usd\config.py", line 170, in <module>
    f"{get_addon_settings_value(get_addon_settings(), ADDON_SETTINGS_LAKE_FS_REPO_URI)}{get_usd_lib_conf_from_lakefs()}"  File "E:\dev\ayon-usd\client\ayon_usd\config.py", line 122, in get_addon_settings
    return ayon_api.get_addon_settings(
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\ayon_api\_api.py", line 1815, in get_addon_settings
    return con.get_addon_settings(*args, **kwargs)
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\ayon_api\server_api.py", line 3255, in get_addon_settings
    return self.get_addon_studio_settings(
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\ayon_api\server_api.py", line 3159, in get_addon_studio_settings
    result.raise_for_status()
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\ayon_api\server_api.py", line 206, in raise_for_status
    raise HTTPRequestERROR(message, exc.response)
ayon_api.exceptions.HTTPRequestERROR: 404 Client ERROR: Not Found for url: http://localhost:5000/api/addons/ayon_usd/1.0.4-dev.37/settings?variant=2024.01.0-full-2024-01-17-02-roydev

Testing notes:

1. Start AYON tray
2. Launch Maya
3. Maya should work with all it env vars (like allow to do import capture)

[BigRoy]

For whatever reason I suddenly couldn't test it because I started getting issues with how the settings load in config.py

Launching tray would give me:

*** WRN: >>> { AddonsLoader }: [  FAILED to import "ayon_usd"  ]
==============================
404 Client ERROR: Not Found for url: http://localhost:5000/api/addons/ayon_usd/1.0.4-dev.37/settings?variant=2024.01.0-full-2024-01-17-02-roydev
==============================
Traceback (most recent call last):
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\ayon_api\server_api.py", line 202, in raise_for_status
    self._response.raise_for_status()
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\requests\models.py", line 1021, in raise_for_status
    raise HTTPERROR(http_ERROR_msg, response=self)
requests.exceptions.HTTPERROR: 404 Client ERROR: Not Found for url: http://localhost:5000/api/addons/ayon_usd/1.0.4-dev.37/settings?variant=2024.01.0-full-2024-01-17-02-roydev

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "E:\dev\ayon-core\client\ayon_core\addon\base.py", line 417, in _load_ayon_addons
    mod = __import__(basename, fromlist=("",))
  File "E:\dev\ayon-usd\client\ayon_usd\__init__.py", line 3, in <module>
    from .addon import USDAddon
  File "E:\dev\ayon-usd\client\ayon_usd\addon.py", line 11, in <module>
    from . import config, utils
  File "E:\dev\ayon-usd\client\ayon_usd\config.py", line 170, in <module>
    f"{get_addon_settings_value(get_addon_settings(), ADDON_SETTINGS_LAKE_FS_REPO_URI)}{get_usd_lib_conf_from_lakefs()}"  File "E:\dev\ayon-usd\client\ayon_usd\config.py", line 122, in get_addon_settings
    return ayon_api.get_addon_settings(
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\ayon_api\_api.py", line 1815, in get_addon_settings
    return con.get_addon_settings(*args, **kwargs)
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\ayon_api\server_api.py", line 3255, in get_addon_settings
    return self.get_addon_studio_settings(
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\ayon_api\server_api.py", line 3159, in get_addon_studio_settings
    result.raise_for_status()
  File "C:\Program Files\Ynput\AYON 1.0.3\dependencies\ayon_api\server_api.py", line 206, in raise_for_status
    raise HTTPRequestERROR(message, exc.response)
ayon_api.exceptions.HTTPRequestERROR: 404 Client ERROR: Not Found for url: http://localhost:5000/api/addons/ayon_usd/1.0.4-dev.37/settings?variant=2024.01.0-full-2024-01-17-02-roydev

So this was due to other issues as explained in #31 - the issue in this case was that it didn't use the addon version number from the bundle, but from the active client - which in my test run mismatched because I had a different server addon version than this branch.

Anyway, since #31 required massive changes I've included this PR in #33. Hence I'm closing this in favor of #33 - if there end up being tons of reasons not to merge #33 we can reopen this one again of course.