first stab at replicating couch nodes

from should probably be a local port and we should use stunnels to
connect to the master
allow setting custom netrc in query and document defines

We need to perform some actions as the replication user for plain couch.
update couch-doc-update to also filter _replication fields

we only need to keep id and rev to prevent conflicts
create netrc files for all users
use replication user for creating the replications
minor lint
Merge branch 'azul-feature/mirror_plain_couch'