dummy HasClient ClientM WebSocket

dummy HasClient ClientM WebSocket

Enough to let lockcontent routes be included and servant-client be used.
But not enough to use servant-client with those routes. May need to
implement a separate runner for that part of the protocol?

Also some misc other stuff needed to use servant-client.

And fix exposing of UUID in the JSON types. UUID does actually have
aeson instances, but they're used elsewhere (metadata --batch, although
only included to get it to compile, not actually used in there) and not
suitable for use here since this must work with every possible UUID.