Map OIDC groups to Orgs/Teams (#21441)

Fixes #19555

Test-Instructions:
https://github.com/go-gitea/gitea/pull/21441#issuecomment-1419438000

This PR implements the mapping of user groups provided by OIDC providers
to orgs teams in Gitea. The main part is a refactoring of the existing
LDAP code to make it usable from different providers.

Refactorings:
- Moved the router auth code from module to service because of import
cycles
- Changed some model methods to take a `Context` parameter
- Moved the mapping code from LDAP to a common location

I've tested it with Keycloak but other providers should work too. The
JSON mapping format is the same as for LDAP.


![grafik](https://user-images.githubusercontent.com/1666336/195634392-3fc540fc-b229-4649-99ac-91ae8e19df2d.png)

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

routers/api/v1/api.go

@@ -507,7 +507,7 @@ func orgAssignment(args ...bool) func(ctx *context.APIContext) {
 
 		var err error
 		if assignOrg {
-			ctx.Org.Organization, err = organization.GetOrgByName(ctx.Params(":org"))
+			ctx.Org.Organization, err = organization.GetOrgByName(ctx, ctx.Params(":org"))
 			if err != nil {
 				if organization.IsErrOrgNotExist(err) {
 					redirectUserID, err := user_model.LookupUserRedirect(ctx.Params(":org"))
@@ -687,7 +687,7 @@ func Routes(ctx gocontext.Context) *web.Route {
 	}
 
 	// Get user from session if logged in.
-	m.Use(context.APIAuth(group))
+	m.Use(auth.APIAuth(group))
 
 	m.Use(context.ToggleAPI(&context.ToggleOptions{
 		SignInRequired: setting.Service.RequireSignInView,