tools: add tools section and tree-sitter link

Add a tools section and a link to tree-sitter-scfg.

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>

Add hare library

fix grammar

add OCaml library

Simplify directive-params in specification

Add scfg-rs, a rust scfg parser

Add link to CC-BY-SA 4.0

ABNF typographic fix

Add link to C implementation

Adding Python module to parse scfg files.

Make it clear nothing's final yet

Add LICENSE

Move implementations section up

Add example

Tweak grammar

Initial commit