Avoid rebuild on production

[ltetrel]

Currently, a binder submission is built from user/repo.git on neurolibre-test (compute canada) and then the image is pushed to our own registry on neurolibre-prod (mcgill). When the binder submission is sent on neurolibre-prod from fork roboneuro/repo.git, it is supposed to get the cached image and avoid docker re-building.
However because the repository name change (user/repo.git -> roboneurolibre/repo.git ) it is still trying to rebuild (but push is much faster because the layers already exists on registry).

[ltetrel]

Suggestion was to use custom name for docker build, however binderhub uses repo link as an internal reference.

[ltetrel]

An easier path would be to actually also launch and build test from roboneurolibre/repo.git and not user/repo.git anymore.
During review and test, whenever we trigger a roboneuro build notebooks through github, it will actually update its fork to get up-to-date version from user.
Not sure if roboneuro could support that @agahkarakuzu