Use environment to configure app.

Updated application.conf files to receive application parameter from environment.
Pass input into java process to automate TC runs, and remove log formatting.
Added listening socket to java process for attach-and-debug.
Make the sbt debugger opt-in.
Update Readme about debugging.
Change the keys to alphanumeric.
Merge pull request #1078 from guardian/parameterise-config

Use environment to configure app.