MM-8796: Full implementation of "Schemes" in Store/Model/App layers. (#8357)

* 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.

store/store.go

@@ -62,6 +62,7 @@ type Store interface {
 	FileInfo() FileInfoStore
 	Reaction() ReactionStore
 	Role() RoleStore
+	Scheme() SchemeStore
 	Job() JobStore
 	UserAccessToken() UserAccessTokenStore
 	ChannelMemberHistory() ChannelMemberHistoryStore
@@ -105,6 +106,7 @@ type TeamStore interface {
 	RemoveAllMembersByTeam(teamId string) StoreChannel
 	RemoveAllMembersByUser(userId string) StoreChannel
 	UpdateLastTeamIconUpdate(teamId string, curTime int64) StoreChannel
+	GetTeamsByScheme(schemeId string, offset int, limit int) StoreChannel
 }
 
 type ChannelStore interface {
@@ -162,6 +164,7 @@ type ChannelStore interface {
 	AnalyticsDeletedTypeCount(teamId string, channelType string) StoreChannel
 	GetChannelUnread(channelId, userId string) StoreChannel
 	ClearCaches()
+	GetChannelsByScheme(schemeId string, offset int, limit int) StoreChannel
 }
 
 type ChannelMemberHistoryStore interface {
@@ -477,5 +480,12 @@ type RoleStore interface {
 	Get(roleId string) StoreChannel
 	GetByName(name string) StoreChannel
 	GetByNames(names []string) StoreChannel
+	Delete(roldId string) StoreChannel
 	PermanentDeleteAll() StoreChannel
 }
+
+type SchemeStore interface {
+	Save(scheme *model.Scheme) StoreChannel
+	Get(schemeId string) StoreChannel
+	Delete(schemeId string) StoreChannel
+}