Add more Git hooks, delegate to .local convention

The `pre-commit` and `prepare-commit-msg` git hooks can be used for some
interesting things such as linting files. For example:

https://github.com/croaky/dotfiles/commit/b3bc7d3f0dff46a47697c8c81a8352b76eb0e3a5
You can put quotes around this entire value, which might look better:

```sh
local_hook="$HOME/.git_template.local/hooks/pre-commit"
```