Remove RSpec configuration

Previously, RSpec was being configured in the application, which was
overriding any settings that a developer would have on their machine.
Removed the configuration from the repository.

https://trello.com/c/1cAk5aFg
Update sample environment variables

Previously, some sensitive data was being stored in the application's
sample environment variables, which was presenting a security issue. The
variables have been updated to use dummy values.

https://trello.com/c/ss5habYR