Add CSP Websocket compatibility

[adriansmares]

Summary

This PR automatically adds Websocket source URLs to the content security policy of the Console and Account app.

Changes

• Automatically add the ws/wss versions of the API base URLs to CSP.

Testing

Unit testing, and also cherry-picked into https://github.com/TheThingsIndustries/lorawan-stack/pull/3953 in order to check with staging1.

Regressions

N/A. The tests cover the behavior. No dedicated testing is required.

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• The steps/process to test this feature are clearly explained including testing for regressions.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.