gitconfig: remote tweaks

* Removes unused remotes;
* Moves  invenio-software remote to the end of the push chain as it's slow.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
invenio-demosite helpers

* bash alias for easy cd in virtualenv;
* git remotes.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>