Chore: Move ReqContext to contexthandler service (#62102)

* Chore: Move ReqContext to contexthandler service

* Rename package to contextmodel

* Generate ngalert files

* Remove unused imports

pkg/services/contexthandler/auth_proxy_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/grafana/grafana/pkg/services/auth/jwt"
 	"github.com/grafana/grafana/pkg/services/authn/authntest"
 	"github.com/grafana/grafana/pkg/services/contexthandler/authproxy"
+	contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
 	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/grafana/grafana/pkg/services/login/loginservice"
 	"github.com/grafana/grafana/pkg/services/org/orgtest"
@@ -42,7 +43,7 @@ func TestInitContextWithAuthProxy_CachedInvalidUserID(t *testing.T) {
 
 	req, err := http.NewRequest("POST", "http://example.com", nil)
 	require.NoError(t, err)
-	ctx := &models.ReqContext{
+	ctx := &contextmodel.ReqContext{
 		Context: &web.Context{Req: req},
 		Logger:  log.New("Test"),
 	}