[MM-27535] User invite limits for MM Cloud (#15197)

* Add a config for MM User Limit

* Adding graceful errors for if an administrator invites people passed their user limit

* Including changed vendor files

* Adding unit test

* Fix a bug

* Push up working tests (Thanks Joram)

* Add more cases, clean up logs in code

* One more case

* Refactoring based on PR comments

* Updating i18n

* Some changes based on PR review

* Remove a comment

* Bring back some translations that were somehow removed

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

go.mod

@@ -85,7 +85,7 @@ require (
 	github.com/remyoudompheng/bigfft v0.0.0-20190728182440-6a916e37a237 // indirect
 	github.com/rs/cors v1.7.0
 	github.com/rudderlabs/analytics-go v3.2.1+incompatible
-	github.com/russellhaering/goxmldsig v0.0.0-20180430223755-7acd5e4a6ef7
+	github.com/russellhaering/goxmldsig v0.0.0-20180430223755-7acd5e4a6ef7 // indirect
 	github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd
 	github.com/segmentio/backo-go v0.0.0-20200129164019-23eae7c10bd3 // indirect
 	github.com/sirupsen/logrus v1.6.0
@@ -108,6 +108,9 @@ require (
 	github.com/wiggin77/merror v1.0.2
 	github.com/wiggin77/srslog v1.0.1
 	github.com/xtgo/uuid v0.0.0-20140804021211-a0b114877d4c // indirect
+	github.com/ziutek/mymysql v1.5.4 // indirect
+	github.com/zmb3/gogetdoc v0.0.0-20190228002656-b37376c5da6a // indirect
+	go.etcd.io/bbolt v1.3.5 // indirect
 	go.uber.org/zap v1.15.0
 	golang.org/x/crypto v0.0.0-20200728195943-123391ffb6de
 	golang.org/x/image v0.0.0-20200618115811-c13761719519
@@ -116,7 +119,8 @@ require (
 	golang.org/x/net v0.0.0-20200707034311-ab3426394381
 	golang.org/x/sys v0.0.0-20200805065543-0cf7623e9dbd // indirect
 	golang.org/x/text v0.3.3
-	golang.org/x/tools v0.0.0-20200626171337-aa94e735be7f
+	golang.org/x/tools v0.0.0-20200806022845-90696ccdc692
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	google.golang.org/appengine v1.6.6 // indirect
 	google.golang.org/genproto v0.0.0-20200626011028-ee7919e894b5 // indirect
 	google.golang.org/grpc v1.30.0 // indirect