various fixes (#36697)

fixes bad address concat causing malformed address
Introduces new config options to for release attachments and number of
files to avoid sharing limits for PR/issue attachments and release ones

Fixes: https://github.com/go-gitea/gitea/issues/31638
Fixes: https://github.com/go-gitea/gitea/issues/35812
Doc update: https://gitea.com/gitea/docs/pulls/348
Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

tests/integration/api_releases_test.go

@@ -335,7 +335,7 @@ func TestAPIDeleteReleaseByTagName(t *testing.T) {
 
 func TestAPIUploadAssetRelease(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
-	defer test.MockVariableValue(&setting.Attachment.MaxSize, 1)()
+	defer test.MockVariableValue(&setting.Repository.Release.FileMaxSize, 1)()
 
 	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
 	owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID})