MB-8828: better error handling in XMem mode XDCR

Today if XMem replicator received some error msgs which
it did not expect to see, it would crash. This behavior is
inherited from CAPI mode XDCR. For XMem mode, we should be
able to do better than that since now we send requests
to remote on a per-mutation basis. Instead of crashing
replicator, this commit will absorb and dump error msgs
from remote memacached into logs.

Change-Id: I950eb8cada03d7742108b8b140318c7ebb4c775d
Reviewed-on: http://review.couchbase.org/28234
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Junyi Xie <junyi.couchbase@gmail.com>
MB-8879: shrink error msgs exposed to UI and logs

Today when errors happened XDCR will dump errors to both xdcr log
and ns_server logs. Some information we dump to these log files is
redundant, causing bloated logs.

Also, XDCR now overwhelms UI ("last 10 errors" on XDCR tab) by
exposing too much info. The Erlang state from crash process is
too big to show on UI and it is unnecessary to show the complete
Erlang state to users.

This commit will shrink xdcr logs and the error msg exposed to UI.

Change-Id: I8863f20193794f52644bb09d804827ff454e3ede
Reviewed-on: http://review.couchbase.org/28256
Reviewed-by: Junyi Xie <junyi.couchbase@gmail.com>
Tested-by: Junyi Xie <junyi.couchbase@gmail.com>
MB-8882: do not propose to create view to read-only admin

Because "Create Development View" button is obviously not available
for this user.

Change-Id: I8c5db4929c55b9e89bcea2bc86ac7f771d6dc079
Reviewed-on: http://review.couchbase.org/28397
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>