The main motivation behind this change is to get just a little telemetry information from nodes on the network, namely the version of Radicle they are running.

This is achieved by rewriting impl Default for UserAgent which now uses the version information provided by the build script also used in other crates.

Also, a new configuration option node.userAgent is added, which allows users to override the user agent if they so please, or set the value null, which will in turn send the user agent /radicle/, which is not really helpful, and the default prior to this commit.

Creations of UserAgent in the whole workspace is cleaned up. In order to do that UserAgent::test is introduced.

Rebase and add test for explicitly setting the default user agent as requested by Fintan.

Changes:

• Rebase
• Rename fake user agent strings to /radicle/runtime/bootstrap and /radicle/message/truncated/
• Remove unnecessary allow(deprecated)