Hoist annotations of common settings to openedx/envs/common.py #37281

Identify settings with annotated descriptions that exist in both lms/envs/common.py and cms/envs/common.py but have different values. For each such setting, move the annotation to openedx/envs/common.py to centralize the shared metadata. We are only considering settings with differing values, since any with the same value should already have been raised up into openedx/envs/common.py.

Things to consider (after verifying there are cases that meet the above criteria):

• Ensure the description is service-variant agnostic, but include service specific details if it is helpful.
• Do we just bring up the annotation, or do we also include a type annotation for the setting?
• Since these values don't have equal values, how do we handle the default_value?