PLT-7503: Create Message Export Scheduled Task and CLI Command (#7612)

* Created message export scheduled task

* Added CLI command to immediately kick off an export job

* Added email addresses for users joining and leaving the channel to the export

* Added support for both MySQL and PostgreSQL

* Fixing gofmt error

* Added a new ChannelMemberHistory store and associated tests

* Updating the ChannelMemberHistory channel as users create/join/leave channels

* Added user email to the message export object so it can be included in the actiance export xml

* Don't fail to log a leave event if a corresponding join event wasn't logged

* Adding copyright notices

* Adding message export settings to daily diagnostics report

* Added System Console integration for message export

* Cleaned up TODOs

* Made batch size configurable

* Added export from timestamp to CLI command

* Made ChannelMemberHistory table updates best effort

* Added a context-based timeout option to the message export CLI

* Minor PR updates/improvements

* Removed unnecessary fields from MessageExport object to reduce query overhead

* Removed JSON functions from the message export query in an effort to optimize performance

* Changed the way that channel member history queries and purges work to better account for edge cases

* Fixing a test I missed with the last refactor

* Added file copy functionality to file backend, improved config validation, added default config values

* Fixed file copy tests

* More concise use of the testing libraries

* Fixed context leak error

* Changed default export path to correctly place an 'export' directory under the 'data' directory

* Can't delete records from a read replica

* Fixed copy file tests

* Start job workers when license is applied, if configured to do so

* Suggestions from the PR

* Moar unit tests

* Fixed test imports

store/sqlstore/supplier.go

@@ -62,29 +62,30 @@ const (
 )
 
 type SqlSupplierOldStores struct {
-	team            store.TeamStore
-	channel         store.ChannelStore
-	post            store.PostStore
-	user            store.UserStore
-	audit           store.AuditStore
-	cluster         store.ClusterDiscoveryStore
-	compliance      store.ComplianceStore
-	session         store.SessionStore
-	oauth           store.OAuthStore
-	system          store.SystemStore
-	webhook         store.WebhookStore
-	command         store.CommandStore
-	commandWebhook  store.CommandWebhookStore
-	preference      store.PreferenceStore
-	license         store.LicenseStore
-	token           store.TokenStore
-	emoji           store.EmojiStore
-	status          store.StatusStore
-	fileInfo        store.FileInfoStore
-	reaction        store.ReactionStore
-	job             store.JobStore
-	userAccessToken store.UserAccessTokenStore
-	plugin          store.PluginStore
+	team                 store.TeamStore
+	channel              store.ChannelStore
+	post                 store.PostStore
+	user                 store.UserStore
+	audit                store.AuditStore
+	cluster              store.ClusterDiscoveryStore
+	compliance           store.ComplianceStore
+	session              store.SessionStore
+	oauth                store.OAuthStore
+	system               store.SystemStore
+	webhook              store.WebhookStore
+	command              store.CommandStore
+	commandWebhook       store.CommandWebhookStore
+	preference           store.PreferenceStore
+	license              store.LicenseStore
+	token                store.TokenStore
+	emoji                store.EmojiStore
+	status               store.StatusStore
+	fileInfo             store.FileInfoStore
+	reaction             store.ReactionStore
+	job                  store.JobStore
+	userAccessToken      store.UserAccessTokenStore
+	plugin               store.PluginStore
+	channelMemberHistory store.ChannelMemberHistoryStore
 }
 
 type SqlSupplier struct {
@@ -130,6 +131,7 @@ func NewSqlSupplier(settings model.SqlSettings, metrics einterfaces.MetricsInter
 	supplier.oldStores.fileInfo = NewSqlFileInfoStore(supplier, metrics)
 	supplier.oldStores.job = NewSqlJobStore(supplier)
 	supplier.oldStores.userAccessToken = NewSqlUserAccessTokenStore(supplier)
+	supplier.oldStores.channelMemberHistory = NewSqlChannelMemberHistoryStore(supplier)
 	supplier.oldStores.plugin = NewSqlPluginStore(supplier)
 
 	initSqlSupplierReactions(supplier)
@@ -801,6 +803,10 @@ func (ss *SqlSupplier) UserAccessToken() store.UserAccessTokenStore {
 	return ss.oldStores.userAccessToken
 }
 
+func (ss *SqlSupplier) ChannelMemberHistory() store.ChannelMemberHistoryStore {
+	return ss.oldStores.channelMemberHistory
+}
+
 func (ss *SqlSupplier) Plugin() store.PluginStore {
 	return ss.oldStores.plugin
 }