feat(pre-commit): Add binary based install

For no additional build dependencies (besides Python >= 3.6), and faster
install.

The setup.py here is a copy of the one at
https://github.com/shellcheck-py/shellcheck-py with changes kept at the
bare minimum for future diffability.

We don't support checksumming at least yet, because there's no access to
them from cargo-release at the moment.

Closes #285

docs/pre-commit.md

@@ -11,6 +11,10 @@ repos:
       - id: typos
 ```
 
+The `typos` id installs a prebuilt executable from GitHub releases. If
+one does not exist for the target platform, or if one built from
+sources is preferred, use `typos-src` as the hook id instead.
+
 Be sure to change `rev` to use the desired `typos` git tag or
 revision.