♻️ Maintenance/new settings (1st round)

[pcrespov]

What do these changes do?

This is the first of a series of PR that will progressively introduce the new-settings (i.e. move from trafaret to settings_library ) in the entire repo. In this PR we address:

✨ settings_library :

• new settings for Prometheus and SMTP (Simple Mail Transfer Protocol)
• new mixin that will be use in settings subclasses to configure services (typically with port, host, etc)
• renaming of modules:
  • distinguish three groups:
    • base modules base prefix
    • settings groups (no prefix)
    • utils with mixins, ... utils_ prefix
    • internal like _constants

♻️ webserver

• reducing coupling between plugins (typically by moving constants to its own module reduces significantly coupling)
• see commits for details (looking at file changes only is not very informative)
• renaming of modules:
  • settings -> application_settings since it goes side-by-side with application_* modules
  • constants -> _constants: to stress it is internal

NOTE: this PR is very "noisy" but in reality there are very few changes: see commits message to guide your review.

Related issue/s

• ⚗️ web-server refactoring backlog #2008 : step towards full conversion to settings-lbirary

How to test

webserver and settingslib tests covers changes

Checklist

[codecov]

Codecov Report

Merging #2736 (d3b1726) into master (1f76deb) will increase coverage by 0.0%.
The diff coverage is 93.2%.

@@          Coverage Diff           @@
##           master   #2736   +/-   ##
======================================
  Coverage    78.2%   78.2%           
======================================
  Files         647     652    +5     
  Lines       26915   26963   +48     
  Branches     2617    2617           
======================================
+ Hits        21062   21106   +44     
- Misses       5144    5146    +2     
- Partials      709     711    +2     

Flag	Coverage Δ
integrationtests	65.6% <89.4%> (-0.1%)	⬇️
unittests	74.0% <93.2%> (+<0.1%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...src/servicelib/aiohttp/web_exceptions_extension.py	0.0% <0.0%> (ø)
...ings-library/src/settings_library/utils_logging.py	87.5% <ø> (ø)
...s/api-server/src/simcore_service_api_server/cli.py	0.0% <0.0%> (ø)
...ore_service_director_v2/utils/client_decorators.py	69.2% <ø> (ø)
...imcore_service_webserver/meta_modeling_handlers.py	73.0% <28.5%> (ø)
...ettings-library/src/settings_library/prometheus.py	91.6% <91.6%> (ø)
...ages/models-library/src/models_library/services.py	100.0% <100.0%> (ø)
...library/src/servicelib/aiohttp/application_keys.py	100.0% <100.0%> (ø)
...ettings-library/src/settings_library/_constants.py	100.0% <100.0%> (ø)
...ttings-library/src/settings_library/basic_types.py	100.0% <100.0%> (ø)
... and 54 more

[sanderegg]

great! please have a look at my comments before merging

[sanderegg]

why is there a _ in front of the module name? it cannot be re-used outside of the library? stuff like GB is not really something private is it?

[pcrespov]

It is a way to say to express what is part of the API of the library and what is not
the constants, as you mention, are not too troublesome regarding coupling BUT this way I avoid having the services importing the same constant from different libraries. That is the ida