better propagate reason of failure to change vbucket filter

In MB-5258 we're seeing vbucket filter change operation to fail, but
it's not obvious why it happened because just 'failed' is
returned. Now we'll return reason why it failed so that it's more
obvious what happened without looking deeply at logs.

Change-Id: I6c9aaffd3e56d9796290b9ea21a986a62734434e
Reviewed-on: http://review.couchbase.org/15788
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
explicitly refuse to failover unknown node. MB-5267

As part of this change we've also got rid of
ns_cluster_membership:failover/1 and replaced it with direct call to
orchestrator. ns_orchestrator:failover/1 typespec is also corrected.

Change-Id: I7f762a08b0bc53f01e235f9d29ea2d3bd6a8fdb8
Reviewed-on: http://review.couchbase.org/15815
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
[cbcollect_info] use cbstats instead of mbstats. MB-5272

Change-Id: Id7acd48e55a034ae7175c9980a0dfde5953e76b5
Reviewed-on: http://review.couchbase.org/15816
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
[cbcollect_info] grab memcached memory stats as well. MB-5273

Change-Id: I137727216e41d7f3cf7fefe0484eb2dc8c1864f0
Reviewed-on: http://review.couchbase.org/15817
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
focus password field on "too short password" error as well

Change-Id: I7a69038bb0365a5d3d15eb90774188325b15563c
Reviewed-on: http://review.couchbase.org/15818
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
gather ep_item_commit_failed for poor man alerts. MB-5256

Change-Id: I15a0de326abbbf510c0ad5982cc74d2e4c142c65
Reviewed-on: http://review.couchbase.org/15819
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
allow dialogs to be not automatically closed on hash change

I'm not sure we should be doing that in default case but default is a
bit not right time to change now. So we have new option to stop that
behavior.

This is needed for next commit that's fixing MB-5275

Change-Id: I8fcb8b15fbb58a488bbbb7cf40b3a1e295153a2c
Reviewed-on: http://review.couchbase.org/15820
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
explicitly consume poor man's alerts. MB-5275

There's now separate POST url to clean currently visible alerts (with
cas-like token, so that no alert messages can be lost). That url is
advertised via alertsSilenceURL attribute of pool details.

This also makes few obvious cleanups in alerts service. Like getting
rid of default handle_call implementation.

Change-Id: Id15be6764122890717c98c9322a710bfae6b7f2a
Reviewed-on: http://review.couchbase.org/15821
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Merge remote-tracking branch 'origin/branch-181' into branch-18

* origin/branch-181:
  explicitly consume poor man's alerts. MB-5275
  allow dialogs to be not automatically closed on hash change
  gather ep_item_commit_failed for poor man alerts. MB-5256
  focus password field on "too short password" error as well
  [cbcollect_info] grab memcached memory stats as well. MB-5273
  [cbcollect_info] use cbstats instead of mbstats. MB-5272
  explicitly refuse to failover unknown node. MB-5267
  better propagate reason of failure to change vbucket filter

Conflicts:
	src/menelaus_web.erl

Change-Id: I4400323fcae27eb45a5a73bea002fd69b38cc15a