Move context from modules to services (#29440)

Since `modules/context` has to depend on `models` and many other
packages, it should be moved from `modules/context` to
`services/context` according to design principles. There is no logic
code change on this PR, only move packages.

- Move `code.gitea.io/gitea/modules/context` to
`code.gitea.io/gitea/services/context`
- Move `code.gitea.io/gitea/modules/contexttest` to
`code.gitea.io/gitea/services/contexttest` because of depending on
context
- Move `code.gitea.io/gitea/modules/upload` to
`code.gitea.io/gitea/services/context/upload` because of depending on
context

services/context/api_org.go

@@ -0,0 +1,12 @@
+// Copyright 2016 The Gogs Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package context
+
+import "code.gitea.io/gitea/models/organization"
+
+// APIOrganization contains organization and team
+type APIOrganization struct {
+	Organization *organization.Organization
+	Team         *organization.Team
+}