Enhance project to allow option for the user to manually pass the SCM
credentials to the release plugin on each release.

Usecase: If you are tracking who 'authorized' a release, easier/more direct to
have the person require to enter their username/password for the release and
have that username used in the SCM logging/auditing. (note: password used for
hudson login likely to be different than SCM password, but could be another
enhancement for either way).