feat: Start using uv

[ividito]

Summary:

Reduces dev dependency installation time by 99% (47.8s on my machine to 400ms - at first, I didn't believe uv sync had actually done anything at all).

I tried to more-or-less follow conventions established by CSDA: https://github.com/NASA-IMPACT/csdap-stac-api/pull/250

Included some minor README updates to match.

Starts some of the dependency/constraint reorganization discussed in #307 - I would like to get this working in the Dockerfiles too, but this will be a lot easier after #348

[botanical]

Yay for uv!! I just had one question.

[amarouane-ABDELHAK]

I am a huge fan of uv and I am in favor of using it. But, SM2A is intended to run in a Docker container for local development to mirror the production environment (as closely as possible). Is the use case for uv here specifically to run unit tests?
After running uv sync, there’s no further guidance on what the user should do next with the virtual environment set up by uv.

[ividito]

@amarouane-ABDELHAK for now, yes, this only improves non-containerized local development and unit testing. I have a follow-up that incorporates uv into our Dockerfiles, which will have more impact on deployment speed and containerized development, but I think this will be easier to implement and merge after #352

[botanical]

Since we're using an updated version of moto, do you mind updating the unit tests that import it? ( I think the mock_s3 imports can now be from moto import mock_aws and all instances of mock_s3 can be updated to use mock_aws.

I also think we need to add smart_open to our pyproject.toml

[botanical]

🔥 thanks for this work