feat: add clientless Redpanda service

[cofin]

Summary\n\n- add a Redpanda service using the official container and bundled rpk CLI\n- support database and server xdist isolation with dynamic advertised ports\n- document the fixture and register one-provider selective CI ownership\n\n## Validation\n\n- provider tests: 6 passed\n- compatibility runner: 34 passed\n- Ruff, mypy, pyright, slotscheck, pre-commit, and docs passed\n- selector: 1 provider job, 1 image pull\n- no Python client dependency or lockfile change\n\nPart of #150.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 36.90476% with 53 lines in your changes missing coverage. Please review.
✅ Project coverage is 2.77%. Comparing base (ba9c758) to head (5664503).

Files with missing lines	Patch %	Lines
src/pytest_databases/docker/redpanda.py	36.90%	53 Missing ⚠️

Additional details and impacted files

@@                  Coverage Diff                   @@
##           feat/podman-support    #155      +/-   ##
======================================================
- Coverage                11.95%   2.77%   -9.19%     
======================================================
  Files                       24      25       +1     
  Lines                     2082    2166      +84     
  Branches                   169     180      +11     
======================================================
- Hits                       249      60     -189     
- Misses                    1798    2106     +308     
+ Partials                    35       0      -35     

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