Simplify oauth (#8972)

* Remove unused OauthProvider::GetIdentifier

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>

* Reuse gitlab's getAuthData() instead of open-coding it

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>

* Remove OauthProvider::GetAuthDataFromJson interface

The data is already available via GetUserFromJson().AuthData

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>

model/gitlab/gitlab.go

@@ -47,7 +47,7 @@ func userFromGitLabUser(glu *GitLabUser) *model.User {
 		user.FirstName = glu.Name
 	}
 	user.Email = glu.Email
-	userId := strconv.FormatInt(glu.Id, 10)
+	userId := glu.getAuthData()
 	user.AuthData = &userId
 	user.AuthService = model.USER_AUTH_SERVICE_GITLAB
 
@@ -90,10 +90,6 @@ func (glu *GitLabUser) getAuthData() string {
 	return strconv.FormatInt(glu.Id, 10)
 }
 
-func (m *GitLabProvider) GetIdentifier() string {
-	return model.USER_AUTH_SERVICE_GITLAB
-}
-
 func (m *GitLabProvider) GetUserFromJson(data io.Reader) *model.User {
 	glu := gitLabUserFromJson(data)
 	if glu.IsValid() {
@@ -102,13 +98,3 @@ func (m *GitLabProvider) GetUserFromJson(data io.Reader) *model.User {
 
 	return &model.User{}
 }
-
-func (m *GitLabProvider) GetAuthDataFromJson(data io.Reader) string {
-	glu := gitLabUserFromJson(data)
-
-	if glu.IsValid() {
-		return glu.getAuthData()
-	}
-
-	return ""
-}