Create software-specific key bindings, such as for emacs

[kyoto7250]

The current key bindings are the gobang defaults, but some users may prefer editor key bindings like emacs or nano.
If anyone can provide these key bindings, we would like to merge them.

---

Expected deliverables

• Create a file under examples/. For example, emacs_key_bind.ron
• A file that can actually be read. It is desirable to have a test. Add a test to src/config.rs.