Auth: Refresh OAuth access_token automatically using the refresh_token (#56076)

* Verify OAuth token expiration for oauth users in the ctx handler middleware

* Use refresh token to get a new access token

* Refactor oauth_token.go

* Add tests for the middleware changes

* Align other tests

* Add tests, wip

* Add more tests

* Add InvalidateOAuthTokens method

* Fix ExpiryDate update to default

* Invalidate OAuth tokens during logout

* Improve logout

* Add more comments

* Cleanup

* Fix import order

* Add error to HasOAuthEntry return values

* add dev debug logs

* Fix tests

Co-authored-by: jguer <joao.guerreiro@grafana.com>

pkg/api/pluginproxy/ds_proxy_test.go

@@ -1065,3 +1065,15 @@ func (m *mockOAuthTokenService) GetCurrentOAuthToken(ctx context.Context, user *
 func (m *mockOAuthTokenService) IsOAuthPassThruEnabled(ds *datasources.DataSource) bool {
 	return m.oAuthEnabled
 }
+
+func (m *mockOAuthTokenService) HasOAuthEntry(context.Context, *user.SignedInUser) (*models.UserAuth, bool, error) {
+	return nil, false, nil
+}
+
+func (m *mockOAuthTokenService) TryTokenRefresh(context.Context, *models.UserAuth) error {
+	return nil
+}
+
+func (m *mockOAuthTokenService) InvalidateOAuthTokens(context.Context, *models.UserAuth) error {
+	return nil
+}