Fix remote upsteam merge errors

[kreynen]

I tried to apply the upstream update for the D8 security update and ran into errors. There is no documentation in the repo that would allow anyone else to update the project.

We need to be able to quickly deploy upstream changes to any forked repo using git rebase upstream/master -Xtheirs where upstream is the https://github.com/pantheon-systems/drops-8

If there are patched versions of core files, we need to re-apply the patch after merging the upstream changes.

[owenmorrill]

https://github.com/CuBoulder/cu-express-drops-8/commits/master

New master branch allows rebasing. We'll still need to resolve conflicts when core changes what the profile inheritance patch touches. We added the readme file in the express profile to explain how to re-add the profile inheritance patch.

[owenmorrill]

https://github.com/CuBoulder/cu-express-drops-8/blob/master/profiles/express/README.md

[owenmorrill]

I'm going to add updating if not fixing the ucb-express-bulletin repo to this ticket as well.

[owenmorrill]

Bulletin has been updated.