Differentiate between omniauth login and import/clone

Currently if adding an omniauth provider such as GitHub you get the ability to login and also clone an existing project using that provider. This is useful for importing projects from GitHub.

It would be useful to be able to specify what a omniauth provider can be used for. Currently I am using SAML as a login provider, and it would be useful to allow importing of projects using GitHub without providing the ability to login to GitLab with GitHub credentials.