[FEATURE] consolodate custom gateway's config files
[CHORE] refactor exchange rate call to a singleton
[CHORE] refactor mailer to a pre-instatiated object, configured AWS secrets
[CHORE] update to new conf file and mailer
[CHORE] update config file
[CHORE] update config file
[CHORE] update conf file, exchange rate module usage
[CHORE] updated to use new mailer