Factorize read render settings code

[sebastienblor]

Changes proposed in this pull request
The code to read render settingts was duplicated between translator/reader and common libs, the later being used for the hydra mode of the usd scene format.
In this PR I'm factorizing the code by moving the code from translator/reader/read_options.cpp to common/rendersettings_utils.cpp so that hydra does exactly the same thing as the procedural. This allowed 7 more tests to succeed in hydra mode (tests needing aov shaders, imagers, etc...)

Issues fixed in this pull request
Fixes #1977

[cpichard]

I have the following compilation error on the CI (darwin+linux):

libs/translator/reader/read_options.cpp:52:12: error: no matching function for call to 'ReadRenderSettings'
   52 |     return ReadRenderSettings(renderSettingsPrim, context, context.GetTimeSettings(), context.GetReader()->GetUniverse(), camTargets.empty() ? SdfPath() : camTargets[0]);

[sebastienblor]

After a small change and the compilation issue seems solved in the CI