Crates.io releases deprecated

[jacobtread]

Description

Warning
Support for crates.io has been discontinued

Pocket Relay is no longer compiling releases for crates.io as the last version released to crates.io was version 5.0, the crates.io release requirements adds additional requirements to the project that affect the project (i.e. requiring the dashboard compiled sources be included in the repository)

If you still want to compile it manually you can refer to the Manual Building
documentation.

Deprecating this allows the server to move forward and remove some of the restrictions imposed by requiring being able to build for crates.io

Checklist

• References to crates.io are removed from README
• Website is updated to remove references to crates.io