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
Actually, since `~/.git_template` is an actual template, `.local` files within it will get stamped out into a repository's `.git/hooks` directory during `git init` calls.

Maybe keeping them in a single `~/.git_template.local` directory is the cleaner, more tidy solution?