API endpoint for changing/creating/deleting multiple files (#24887)

This PR creates an API endpoint for creating/updating/deleting multiple
files in one API call similar to the solution provided by
[GitLab](https://docs.gitlab.com/ee/api/commits.html#create-a-commit-with-multiple-files-and-actions).

To archive this, the CreateOrUpdateRepoFile and DeleteRepoFIle functions
in files service are unified into one function supporting multiple files
and actions.

Resolves #14619

modules/structs/repo_file.go

@@ -64,6 +64,35 @@ func (o *UpdateFileOptions) Branch() string {
 	return o.FileOptions.BranchName
 }
 
+// ChangeFileOperation for creating, updating or deleting a file
+type ChangeFileOperation struct {
+	// indicates what to do with the file
+	// required: true
+	// enum: create,update,delete
+	Operation string `json:"operation" binding:"Required"`
+	// path to the existing or new file
+	Path string `json:"path" binding:"MaxSize(500)"`
+	// content must be base64 encoded
+	// required: true
+	Content string `json:"content"`
+	// sha is the SHA for the file that already exists, required for update, delete
+	SHA string `json:"sha"`
+	// old path of the file to move
+	FromPath string `json:"from_path"`
+}
+
+// ChangeFilesOptions options for creating, updating or deleting multiple files
+// Note: `author` and `committer` are optional (if only one is given, it will be used for the other, otherwise the authenticated user will be used)
+type ChangeFilesOptions struct {
+	FileOptions
+	Files []*ChangeFileOperation `json:"files"`
+}
+
+// Branch returns branch name
+func (o *ChangeFilesOptions) Branch() string {
+	return o.FileOptions.BranchName
+}
+
 // FileOptionInterface provides a unified interface for the different file options
 type FileOptionInterface interface {
 	Branch() string
@@ -126,6 +155,13 @@ type FileResponse struct {
 	Verification *PayloadCommitVerification `json:"verification"`
 }
 
+// FilesResponse contains information about multiple files from a repo
+type FilesResponse struct {
+	Files        []*ContentsResponse        `json:"files"`
+	Commit       *FileCommitResponse        `json:"commit"`
+	Verification *PayloadCommitVerification `json:"verification"`
+}
+
 // FileDeleteResponse contains information about a repo's file that was deleted
 type FileDeleteResponse struct {
 	Content      interface{}                `json:"content"` // to be set to nil