Add information on how to cite AqNWB

[oruebel]

• Add citation information link to README.md
• Add citation information to the legal page in the docs
• Update JOSS paper bibtex entry once published
• ADD RRID URL link for AqNWB record once published

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.39%. Comparing base (dc3d5b4) to head (a24412f).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #291   +/-   ##
=======================================
  Coverage   84.39%   84.39%           
=======================================
  Files          57       57           
  Lines        2569     2569           
  Branches      327      327           
=======================================
  Hits         2168     2168           
  Misses        401      401           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.