Migrate to WebAPI (fix routing)

[kiliankoe]

Since EFA is going to be shut down at some point in the rather near future, it seems like a good idea to use the chance to migrate to use the WebAPI instead and also replace the widgets endpoint while at it.

Big upside is a whole bunch of new data being supplied by the WebAPI.

[kiliankoe]

Looks like EFA is gone. Anything depending on the routing info from here will now be broken 😕 I've already started the migration on the webapi branch, but it's not done yet.