Add git hash text to html document

[ledm]

We're starting to see external users post bgcval2 compare reports on jasmin. As we're going to be starting to help them debug issues and work from there, it would be useful to put some kind of version ID into the html page. Probably at the footer.

[valeriupredoi]

agreed, how about I release a Release Candidate and we'll have something like 1.0rc0 for it? Then, when we are confident with a decent release, we ca change that to an actual 1.0 stable