Add search engine support for files (#16190)

* Add search engine support for files

* Fixing i18n

* Fix golangci-lint

* Fix consistency problem in the Search receiver functio of the SqlFileStore

* Fixing some tests

* Fixing test

* Apply suggestions from code review

Co-authored-by: Mario de Frutos Dieguez <mario@defrutos.org>

* Addressing PR review comments

* Removing some empty lines

* Address PR review comments

* Fixing problem after merge master

* Fixing spelling problem

* Add missed translations

* Fixing certain global variable usages after merge master

* Fixing some constants usage

* Fixing goimports order

Co-authored-by: Mario de Frutos Dieguez <mario@defrutos.org>

einterfaces/mocks/MetricsInterface.go

@@ -75,6 +75,16 @@ func (_m *MetricsInterface) IncrementEtagMissCounter(route string) {
 	_m.Called(route)
 }
 
+// IncrementFileIndexCounter provides a mock function with given fields:
+func (_m *MetricsInterface) IncrementFileIndexCounter() {
+	_m.Called()
+}
+
+// IncrementFilesSearchCounter provides a mock function with given fields:
+func (_m *MetricsInterface) IncrementFilesSearchCounter() {
+	_m.Called()
+}
+
 // IncrementHttpError provides a mock function with given fields:
 func (_m *MetricsInterface) IncrementHttpError() {
 	_m.Called()
@@ -205,6 +215,11 @@ func (_m *MetricsInterface) ObserveEnabledUsers(users int64) {
 	_m.Called(users)
 }
 
+// ObserveFilesSearchDuration provides a mock function with given fields: elapsed
+func (_m *MetricsInterface) ObserveFilesSearchDuration(elapsed float64) {
+	_m.Called(elapsed)
+}
+
 // ObservePluginApiDuration provides a mock function with given fields: pluginID, apiName, success, elapsed
 func (_m *MetricsInterface) ObservePluginApiDuration(pluginID string, apiName string, success bool, elapsed float64) {
 	_m.Called(pluginID, apiName, success, elapsed)