extract webserver into subcrate

[syphar]

This will be the biggest PR of the whole bunch. A good part of the filecount are the moved, unchanged assets.

There is a new approach around the global app context I'm trying here, will adapt the other binaries too when finished.

Next steps are:

• docs.rs-cli stuff into subcrate (migrations, some of the small commands to update priorities, ....)
• perhaps the legacy binary into a subcrate too, at least clean up

[syphar]

ping @GuillaumeGomez only in case you didn't see it.

( take your time if you need it :) )

[GuillaumeGomez]

Nah, just waiting for you to be done with changes. :)