Update SCCB request template for new deployment options
This MR updates the SCCB request template job with some pedantry, but mainly do include the new Other
deployment check box (see https://git.ligo.org/computing/sccb/-/merge_requests/11+), and to abstract the URL linked to describe the continuous deployment to a variable that projects can customise (defaulting to the current gwcelery URL).
Users of this template shouldn't have to do anything to accommodate this change, but can now easily use the template for other projects.
cc @leo-singer