feat(templates): allow managing git based templates [EE-2600] (#7855)

Co-authored-by: itsconquest <william.conquest@portainer.io>
Co-authored-by: oscarzhou <oscar.zhou@portainer.io>
Co-authored-by: Chaim Lev-Ari <chiptus@users.noreply.github.com>

api/http/handler/gitops/handler.go

@@ -0,0 +1,33 @@
+package gitops
+
+import (
+	"net/http"
+
+	"github.com/gorilla/mux"
+	httperror "github.com/portainer/libhttp/error"
+	portainer "github.com/portainer/portainer/api"
+	"github.com/portainer/portainer/api/dataservices"
+	"github.com/portainer/portainer/api/http/security"
+)
+
+// Handler is the HTTP handler used to handle git repo operation
+type Handler struct {
+	*mux.Router
+	dataStore   dataservices.DataStore
+	gitService  portainer.GitService
+	fileService portainer.FileService
+}
+
+func NewHandler(bouncer *security.RequestBouncer, dataStore dataservices.DataStore, gitService portainer.GitService, fileService portainer.FileService) *Handler {
+	h := &Handler{
+		Router:      mux.NewRouter(),
+		dataStore:   dataStore,
+		gitService:  gitService,
+		fileService: fileService,
+	}
+
+	h.Handle("/gitops/repo/file/preview",
+		bouncer.AuthenticatedAccess(httperror.LoggerHandler(h.gitOperationRepoFilePreview))).Methods(http.MethodPost)
+
+	return h
+}