First versioned release

This is the first release of rethink with an actual version number. It introduces several useful changes, most notably the option to run as a Home Assistant App (add-on). Thanks to @stkang90 for the initial version of the add-on code.

Other improvements made recently:

• the CA is now serving leaf certificates for TLS endpoints instead of being the leaf certificate, this improves compatibility with some devices
• added support for custom DNS servers for bridge mode, so that it can bypass the DNS redirect
• configurability improvements for running behind a reverse proxy
• improved bridge mode operation (based on a commit by @3735943886)