What this PR does / why we need it:

This PR makes a number of changes to the make commands and dev guide:

• docs now recommend using uv for setting up local development. I changed env install step (step 9) to run make install-python-ci-dependencies-uv, which differs from the current version in 2 ways: 1) It's using uv instead of pip 2) It's installing package versions from the lock file rather than resolving versions from pypi. This will make local env more predictable and comparable to ci environment which uses the same make command. (Let me know if you disagree with this...)
• Changed all lock-python commands to use uv instead of pip-tools. dev guide now recommends the usage of lock-python-dependencies-all command to update lock files. This command relies on uv and pixi to update lock files for all python versions. (if you want to avoid pixi dependency, you can still run individual commands for each python env) Note that it's important that we all switch to using uv for lock file updates as lock files generated aren't 100% identical to pip-tools generates files in terms of formatting. (see diffs in this PR for an example, the biggest difference is that uv doesn't add feast (setup.py) comment in the files) If some people still keep using pip-tools and others switch to uv for locking, we will generate unnecessary formatting diffs in lock files.