Add gitignore for the uv install on Evergreen (#931)

# Summary
With #884 we started installing uv within the project directory on
Evergreen to get around inconsistent uv versions across build hosts.
However I forgot to gitignore it and now [the PCT bot added the uv
installation artifacts to a
commit](https://github.com/mongodb/mongodb-kubernetes/pull/904/changes#diff-1eee8299f11a78796551ad552091264702e7ecd712e4bafb694883031567cd51)
from within a CI task. This change adds the uv installation directory to
gitignore and cleans up the uv binaries that made their way into the
repo.

## Proof of Work
Passing lint task.

## Checklist

- [ ] Have you linked a jira ticket and/or is the ticket in the title?
- [ ] Have you checked whether your jira ticket required DOCSP changes?
- [ ] Have you added changelog file?
    - use `skip-changelog` label if not needed
- refer to [Changelog files and Release
Notes](https://github.com/mongodb/mongodb-kubernetes/blob/master/CONTRIBUTING.md#changelog-files-and-release-notes)
section in CONTRIBUTING.md for more details

Co-authored-by: Maciej Karaś <maciej.karas@mongodb.com>

Author: fealebenpae

.gitignore

@@ -31,6 +31,9 @@ __debug_bin*
 scripts/dev/contexts/private-context
 scripts/dev/contexts/private-context-*
 
+# On Evergreen we install uv in the project directory, so make sure it's ignored
+/.uv
+
 # These files get generated by emacs and sometimes they are still present when committing
 **/flycheck_*