Add option to prohibit fork if user reached maximum limit of repositories (#21848)

If user has reached the maximum limit of repositories:

- Before
  - disallow create
  - allow fork without limit
- This patch:
  - disallow create
  - disallow fork
- Add option `ALLOW_FORK_WITHOUT_MAXIMUM_LIMIT` (Default **true**) :
enable this allow user fork repositories without maximum number limit

fixed https://github.com/go-gitea/gitea/issues/21847

Signed-off-by: Xinyu Zhou <i@sourcehut.net>

routers/api/v1/repo/fork.go

@@ -141,7 +141,7 @@ func CreateFork(ctx *context.APIContext) {
 		Description: repo.Description,
 	})
 	if err != nil {
-		if repo_model.IsErrRepoAlreadyExist(err) {
+		if repo_model.IsErrReachLimitOfRepo(err) || repo_model.IsErrRepoAlreadyExist(err) {
 			ctx.Error(http.StatusConflict, "ForkRepository", err)
 		} else {
 			ctx.Error(http.StatusInternalServerError, "ForkRepository", err)