Reduce the number of `bind` needed

If a function 'f' calls a function 'g' where 'g' is a configurable,
remove any argumentfs from 'f' which are solely used to call 'g' and
which are 'configurable' by binding 'g'

This removes the need to (consistently) bind both 'f' and 'g', and
instead only requires 'g' to be bound. Basically, bind-able arguments
which only exist to configure layers 'below' the current should not
be there.

In addition, add dedicated python 'HltSourceID' enum, and add a single
mapping of process-id to source-id. Use this 'HltSourceID' to verify
the validity of arguments.