Expand pre-commit config

[jbampton]

Add license header and fill out config and add two more "meta" hooks

[sbp]

@jbampton I usually commit and then push straight away. It's very rare that I would commit multiple and then push, or commit and then push much later, so I think we should use commit only, which I believe is the default?

For minimum_pre_commit_version, I think we should just omit it, because what if people want to use prek? Or does prek ignore this field? It's good to pin or narrow version ranges, but I'm not sure what our minimum actual dependency on pre-commit is here.

For some reason the identity check prints a list of every single file in the repo. Is there a way to turn that behaviour off?

[jbampton]

I just saw the identity hook is actually a debugging hook. Looks like we could remove this.

https://pre-commit.com/#meta-identity