Serve .well-known content

[jace]

The .well-known folder from RFC 5785 has multiple use cases:

1. To host files like /.well-known/assetlinks.json and /.well-known/apple-app-site-association. These are app data and should be stored in version control.

2. To create a temporary file in /.well-known/acme-challenge/ for the purpose of site verification for a TLS certificate. These are not app data and should not be in version control.

Baseframe already handles pre-RFC 5785 static files like /favicon.ico, /robots.txt and /humans.txt, looking for the appropriate file in the app's static folder and defaulting to Baseframe's versions. It should support the .well-known folder as well.

1. Apps should host a static/.well-known folder, and should add static/.well-known/acme-challenge/ to .gitignore (add this in hgapp first)
2. Baseframe should handle .well-known/<path:filename> and serve from the app's static folder.
3. Nginx or other web server can directly serve this folder, similar to the hardcoded handling of the static folder. We don't document Nginx settings in version control anywhere, but should do this in hasdev.

[jace]

@iambibhas You'll need to change our Let's Encrypt usage to match.

[jace]

hasgeek/lastuser@9f5377c demonstrates the problem with static files. It includes a hardcoded reference to auth.hasgeek.com, but the source code shouldn't assume where it will be hosted. We need a build stage for these files. Re-opening this ticket until there's another ticket on handling the build stage.