[Feature]: Bundle user facing docs as part of the frontend.

[ikreymer]

What change would you like to see?

We should have the user-facing docs (docs.browsertrix.com) also available as part of the frontend, probably at /docs/

Context

The docs (hosted at docs.browsertrix.com) are increasingly referenced throughout the UI, especially during workflow setup.
Users shouldn't have to rely on externally hosted docs (which may be at a different version).
Instead, the app should serve the docs at /docs by default.

A custom URL like docsUrl can be provided in the helm chart, which will then enable a redirect of /docs -> docsUrl