Crate braces

This is an empty crate yet to be implemented.

The idea is to do bash brace-expansion:

• bash documentaion: https://www.gnu.org/software/bash/manual/html_node/Brace-Expansion.html
• bash implementation: https://github.com/bminor/bash/blob/master/braces.c
• bash tests: https://github.com/bminor/bash/blob/master/tests/braces.tests