feat: mlm extension added missing migrations, bugfixes

[jonas-hurst]

Description:
Continuation of #1571
Adjusted mlm extension code to the new extension framework. Added missing migrations, fixed bugs and typos

Did not make any code changes since reviewed by @romeokienzler in the last PR. Only moved the code to match the new extension framework.

PR Checklist:

• Pre-commit hooks pass (run pre-commit run --all-files)
• Tests pass (run pytest)
• Documentation has been updated to reflect changes, if applicable
• This PR maintains or improves overall codebase code coverage
• This PR's title is formatted per conventional commits

[jonas-hurst]

Regarding question #1571 (review) :
There are extension fields (e.g. mlm:name, mlm:architecture) that can be applied on the item level or the asset level. Further, there are fields that exclusively extend the asset (e.g. mlm:artifact_type). Hence the difference between AssetGeneralMLMExtension and AssetDetailedMLMExtension.
When extending an asset we need to figure out which of the two we should use, so presence of required property mlm:architecture indicates that we deal with AssetDetailedMLMExtension.
The spec states: the mlm:name should always be provided in the Item properties, so using the required field mlm:architecture instead in the asset is a better indicator.

[jonas-hurst]

to resolve mypy issues:

• installed types-requests library into dev group (reported by cicd pipelines)
• removed type:ignore comments from core/pystac/utils.py

core/pystac/utils.py:490: error: Unused "type: ignore" comment  [unused-ignore]
core/pystac/utils.py:493: error: Unused "type: ignore" comment  [unused-ignore]
core/pystac/utils.py:494: error: Unused "type: ignore" comment  [unused-ignore]
Found 3 errors in 1 file (checked 127 source files)