MM-28861 Marketplace feature flags (#16451)

* Installing plugins specified by feature flags using the marketplace.

* Switch back to using getplugins client.

* Respect disabling automatic installation of pluings.

* pluginid -> plugin_id

* Debug logs for enable plugin error

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

model/feature_flags.go

@@ -3,6 +3,8 @@
 
 package model
 
+import "reflect"
+
 type FeatureFlags struct {
 	// Exists only for unit and manual testing.
 	// When set to a value, will be returned by the ping endpoint.
@@ -13,10 +15,35 @@ type FeatureFlags struct {
 
 	// Toggle on and off scheduled jobs for cloud user limit emails see MM-29999
 	CloudDelinquentEmailJobsEnabled bool
+
+	// Feature flags to control plugin versions
+	PluginIncidentManagement string `plugin_id:"com.mattermost.plugin-incident-management"`
 }
 
 func (f *FeatureFlags) SetDefaults() {
 	f.TestFeature = "off"
 	f.TestBoolFeature = false
 	f.CloudDelinquentEmailJobsEnabled = false
+
+	f.PluginIncidentManagement = "1.1.1"
+}
+
+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
 }