Add workflows to publish divviup-cli and divviup-client to crates.io

[inahga]

So that subscribers can cargo install divviup-cli without the --git argument.

[jbr]

I updated the title because this is more of a "set up a reusable workflow" than a one off "publish from local machine"

[tgeoghegan]

This is done by #783, right? AFAICT the new workflow creates a release, which will trigger .github/workflows/publish-crates.yml. @inahga would you please close this unless there's something else you want to do here?

[inahga]

Moreso accomplished by @jbr in #595, but yes in any case. I can cargo install divviup-cli just fine now.