Move project files into models/project sub package (#17704)

* Move project files into models/project sub package

* Fix test

* Fix test

* Fix test

* Fix build

* Fix test

* Fix template bug

* Fix bug

* Fix lint

* Fix test

* Fix import

* Improve codes

Co-authored-by: 6543 <6543@obermui.de>

models/project/main_test.go

@@ -0,0 +1,23 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package project
+
+import (
+	"path/filepath"
+	"testing"
+
+	"code.gitea.io/gitea/models/unittest"
+
+	_ "code.gitea.io/gitea/models/repo"
+)
+
+func TestMain(m *testing.M) {
+	unittest.MainTest(m, filepath.Join("..", ".."),
+		"project.yml",
+		"project_board.yml",
+		"project_issue.yml",
+		"repository.yml",
+	)
+}