MM-53355: tidy up plugins (#24194)

* remove feature flag managed plugins

* remove unneeded plugin blocklist

* remove unnecessary wrappers

* documentation and logging improvements

* avoid use of global logger
* leverage wrapped loggers (e.g. consistently log `plugin_id`)
* promote some logs from `Debug` to `Info` for better visibility.
* extract installPluginToFilestore
* rename some variables for consistency / clarity

* make generated

server/public/model/feature_flags.go

@@ -22,12 +22,6 @@ type FeatureFlags struct {
 	// AppsEnabled toggles the Apps framework functionalities both in server and client side
 	AppsEnabled bool
 
-	// Feature flags to control plugin versions
-	PluginPlaybooks  string `plugin_id:"playbooks"`
-	PluginApps       string `plugin_id:"com.mattermost.apps"`
-	PluginFocalboard string `plugin_id:"focalboard"`
-	PluginCalls      string `plugin_id:"com.mattermost.calls"`
-
 	PermalinkPreviews bool
 
 	// CallsEnabled controls whether or not the Calls plugin should be enabled
@@ -64,8 +58,6 @@ func (f *FeatureFlags) SetDefaults() {
 	f.TestBoolFeature = false
 	f.EnableRemoteClusterService = false
 	f.AppsEnabled = true
-	f.PluginApps = ""
-	f.PluginFocalboard = ""
 	f.BoardsDataRetention = false
 	f.NormalizeLdapDNs = false
 	f.GraphQL = false
@@ -79,26 +71,6 @@ func (f *FeatureFlags) SetDefaults() {
 	f.DataRetentionConcurrencyEnabled = true
 }
 
-func (f *FeatureFlags) Plugins() map[string]string {
-	rFFVal := reflect.ValueOf(f).Elem()
-	rFFType := reflect.TypeOf(f).Elem()
-
-	pluginVersions := make(map[string]string)
-	for i := 0; i < rFFVal.NumField(); i++ {
-		rFieldVal := rFFVal.Field(i)
-		rFieldType := rFFType.Field(i)
-
-		pluginId, hasPluginId := rFieldType.Tag.Lookup("plugin_id")
-		if !hasPluginId {
-			continue
-		}
-
-		pluginVersions[pluginId] = rFieldVal.String()
-	}
-
-	return pluginVersions
-}
-
 // ToMap returns the feature flags as a map[string]string
 // Supports boolean and string feature flags.
 func (f *FeatureFlags) ToMap() map[string]string {