[CI] Automatically release nightly Catalyst builds on TestPyPI

[dime10]

Other developers, projects, CI tools, and users have often needed to use a recent development version of Catalyst, without being able to do so. The main avenue of obtaining a development version of Catalyst has been building from source.

This PR adds a new action that automatically releases a snapshot of Catalyst on schedule (every night). The package version is automatically bumped (e.g. from 0.8.0-dev0 to 0.8.0-dev1) each time this happens and the main branch updated accordingly.

Testing procedure:

• ~(pre-PR): test action on local fork~
• ~temporarily enable action run on PRs~
• ~(1): test action without branch push or upload~ https://github.com/PennyLaneAI/catalyst/actions/runs/9894753620
• ~(2): test action with upload~ https://github.com/PennyLaneAI/catalyst/actions/runs/9896594944
• ~(3): test action with push to branch~ (I won't be testing this one since since PR workflows don't run on a branch, but it worked on the fork.)
• ~remove all temporary elements from PR~ & merge

[sc-66377]

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 97.98%. Comparing base (9cfe660) to head (8287c23). Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #921 +/- ## ======================================= Coverage 97.98% 97.98% ======================================= Files 71 71 Lines 10497 10546 +49 Branches 956 960 +4 ======================================= + Hits 10285 10334 +49 Misses 169 169 Partials 43 43 ```

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[github-actions[bot]]

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