Add functionality for secrets.js

[sulsanaul]

For developers who clone this project and want to make their own code public, it's a hassle to change sensitive information to (e.g. jsmith => ) whenever they commit a file containing the issue. The solution is to add a secrets.js script ignored by git to export the information to relevant files. A public secrets_template.js exists to outline the behavior of the local secrets.js.

[bryantheastronaut]

Thanks for doing this! I definitely fell behind in PR upkeep. I originally didn't think this would become as used as it is, so I didn't put much thought into securing secrets.

[sulsanaul]

Glad I could help. This repo has been really useful!