Master -> Main Rename

[dannylamb]

Bucket to hold all the PRs I'll make to do this. It's gonna be a lot.

[ysuarez]

I noticed that Melissa is not currently listed as committer. I was told that this may have been committed or at least a PR existed, but on the master branch. This may be a symptom of the transition to the use of the "main" branch.

[jonathangreen]

+1 @ysuarez

There have been a couple comments on the individual PRs but I'm going to link out to them here so they don't get lost:
#1596 (comment)
islandora-deprecated/ansible-role-grok#9 (comment)

[dannylamb]

I've been working my way through Islandora-Devops and sorting out main / master shenanigans with assists from @rosiel. It's almost there. And the Islandora org is close, too, but there's still a lot to do here.