Fix builds

This fixes the build script, as well as the release builds made for Windows and MacOS.
There's other CSS improvements to the frontend as well.

Cleanup

• Change Room Code length to 4, plus made it wasily changeable in the future
• Improve error messages, documentation, and configuration setup

Initial release

First release, with recv CLI and recv server binaries.

Provides support for creating and joining rooms, and sending text.