[MM-16376] Allow server to download and install a plugin from… (#11372)

* Initial implementation of plugin remote source

* Implement API route

* Test API route

* Add i18n

* Handle different error cases in API route

* Include missing i18n translation

* Include AllowInsecureDownloadUrl in telemetry capture

* Updates from PR feedback

* Use HTTPService instead of http.Get

* Remove InstallPluginFromUrlForced from client4

* Use net/url library to inspect url scheme

* remove PluginDownloadUrl from web/params.go

* Allow plugin downloads from internal sources

app/diagnostics.go

@@ -581,6 +581,7 @@ func (a *App) trackConfig() {
 		"enable_zoom":                   pluginActivated(cfg.PluginSettings.PluginStates, "zoom"),
 		"enable":                        *cfg.PluginSettings.Enable,
 		"enable_uploads":                *cfg.PluginSettings.EnableUploads,
+		"allow_insecure_download_url":   *cfg.PluginSettings.AllowInsecureDownloadUrl,
 	})
 
 	a.SendDiagnostic(TRACK_CONFIG_DATA_RETENTION, map[string]interface{}{