Add a deprecation notice for the legacy Python client

[arielshaqed]

We can point at this in announcements and if users ask questions that it covers.

Previously #8195 changed the description of the Python client. I intentionally do not want a link from the PyPI description to here: that description should be terse and say in one sentence what is the package and why you should not use it.

[github-actions[bot]]

:recycle: PR Preview 1e4ed2d1e0dcf5b801c82f26b47ee4e4912dbbba has been successfully destroyed since this PR has been closed.

_{🤖 By surge-preview}

[arielshaqed]

We do not need to make as much noise for Java: it has been labelled "lakeFS OpenAPI Java client legacy SDK" since before 1.0, people know.

[github-actions[bot]]

E2E Test Results - DynamoDB Local - Local Block Adapter

[github-actions[bot]]

E2E Test Results - Quickstart

[arielshaqed]

• Happy to merge this elsewhere, just say where!
• Feel free to merge if you like & don't want to move it.

[arielshaqed]

Thanks!