Set up config options for values that are currently hardcoded

[mpejcoch]

Use the app := &cli.App struct in cmd/mms/main.go, provided via the urfave/cli library

[vkbo]

Should we close this now since the urfave/cli part has been implemented? Loading from multiple config locations should be a new issue as it isn't really described in this issue.

[vkbo]

File location now separated out into issue #43