Add missing keyword arg names to visualization bindings

[djkeyes]

Type

• Bug fix (non-breaking change which fixes an issue): Fixes #
• New feature (non-breaking change which adds functionality). Resolves #
• Breaking change (fix or feature that would cause existing functionality to not work as expected) Resolves #

Motivation and Context

I was using the python visualization API, and I noticed that some of the keyword arguments in the python bindings show up as "arg0" "arg1" etc. This made it confusing, because I had to keep switching between the python API and the source code to see what the arguments really meant. This adds the missing argument names.

Checklist:

• I have run python util/check_style.py --apply to apply Open3D code style
  to my code.
• This PR changes Open3D behavior or adds new functionality.
  • Both C++ (Doxygen) and Python (Sphinx / Google style) documentation is
    updated accordingly.
  • I have added or updated C++ and / or Python unit tests OR included test
    results (e.g. screenshots or numbers) here.
• I will follow up and update the code if CI fails.
• For fork PRs, I have selected Allow edits from maintainers.

Description

Before, if I ran something like help(open3d.visualization.Visualizer.reset_view_point), I would get a message that looks like this (notice the arg0):

Help on instancemethod in module open3d.cpu.pybind.visualization:

reset_view_point(...)
    reset_view_point(self, arg0)
    Function to reset view point
    
    Args:
        arg0 (bool)
    
    Returns:
        None

Now it looks like this:

Help on instancemethod in module open3d.cpu.pybind.visualization:

reset_view_point(...)
    reset_view_point(self, reset_bounding_box=False)
    Function to reset view point
    
    Args:
        reset_bounding_box (bool, optional, default=False): Set to ``False`` to keep current viewpoint
    
    Returns:
        None

I have added similar fixes for other functions in open3d.visualization. I believe this is the only module where the keyword arguments were missing in the python docs. In O3DVisualizer, some of the documentation style was inconsistent, so I cleaned that up, too.

I checked the generated html docs and verified that the results look okay. Let me know if you'd like any other changes.

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This change is 

[update-docs]

Thanks for submitting this pull request! The maintainers of this repository would appreciate if you could update the CHANGELOG.md based on your changes.

[ssheorey]

Thanks @djkeyes for this very useful update!