* Members Save Multiple
* Multiple Channel Members implemented
* Working version with member multi save and multi update
* Adding tests to the save multiple team members store methods
* Tests passing for SaveMember
* Adding remove members tests
* Working on channel store tests
* More work on testing properly SaveMember and SaveMultipleMembers on channels
* More work on testing properly SaveMember and SaveMultipleMembers on teams
* Adding tests for update multiple members for team
* Adding tests for update multiple members for channel
* Fixing some tets
* Fixing tests
* Fixing tests
* Fixing i18n
* Addressing govet problems
* Addressing govet problems
* Addressing govet problems
* Addressing govet problems
* Addressing PR comments (and removing TODO)
* Addressing PR comments
* Fixed broken test
* Removing unnecesary i18n translation string
* Consistent license message for all the go files
* Fixing the last set of unconsistencies with the license headers
* Addressing PR review comments
* Fixing busy.go and busy_test.go license header
* MM-15021: Adding new builtin system schema for Guests
* Fixing tests
* Setting properly the permissions
* Adding guests to sampledata
* Restrict more roles updates in the app layer for guests
* Adding comment to explain that permissions migration must go at the end
* Setting the default guest role for custom scheme during migration
* Fixing import and export
* Creating scheme guest roles on migration
* Fixing tests
* Fixing tests
* Fixing tests
* Add Scheme model and stub store.
* Port ChannelStore to be Scheme aware.
* Make almost all the API/APP layer work with ChannelSchemes.
Only thing still hacky is UpdateChannelMemberRoles().
* Add basic SchemeStore implementation.
* Migrate UpdateChannelMemberRoles properly and fix tests.
* Update store tests and mocks so they work.
* Include creating default roles in Scheme create store function.
* Implement role deletion and start scheme deletion.
* Only use non-deleted roles for authorization.
* Add GetByScheme method to Team store.
* Add GetChannelsByScheme.
* Update store mocks.
* Implement scheme deletion in the store.
* Rename is valid function.
* Add offset and limit to queries to fetch teams and channels by scheme.
* Fix queries.
* Implement scheme awareness in Team store and add a migration.
* Tidy up ChannelStore mapping functions and add exhaustive unit tests.
* Add all missing i18n.
* Proper tests for TeamStore internal functions and fix them.
* Make additional TeamMember fields nullable.
* Make new ChannelMember fields nullable.
* Create new nullable columns without defaults.
* Make new fields in large tables nullalble.
* Fix empty list of TeamMembers.
* Deduplicate SQL queries.
* Fix spelling.
* Fix review comment.
* More review fixes.
* More review fixes.
