This stands as an alternative to using OAuth to access a user's Github
repositories. This is setup in such a way that it can be used without OAuth
configuration.
From a UI perspective, the how to import modal has been replaced by a full
page, which includes a form for posting a personal access token back to the
Import::GithubController.
If the user has logged in via GitHub, skip the Personal Access Token and go
directly to Github for an access token via OAuth.
and request them each session. Pass these tokens to the project import data.
This prevents the need to encrypt these tokens and clear them in case they
expire or get revoked.
For example, if you deleted and re-created OAuth2 keys for Bitbucket, you would get
an Error 500 with no way to recover:
```
Started GET "/import/bitbucket/status" for x.x.x.x at 2015-08-07 05:24:10 +0000
Processing by Import::BitbucketController#status as HTML
Completed 500 Internal Server Error in 607ms (ActiveRecord: 2.3ms)
NameError (uninitialized constant Import::BitbucketController::Unauthorized):
app/controllers/import/bitbucket_controller.rb:77:in `rescue in go_to_bitbucket_for_permissions'
app/controllers/import/bitbucket_controller.rb:74:in `go_to_bitbucket_for_permissions'
app/controllers/import/bitbucket_controller.rb:86:in `bitbucket_unauthorized'
```
Closes#1871
