Release 3.28.0 rc1

### Fixed Bugs:
- Mac installation instructions
- Remove duplicate ExternalAccounts controller actions
- Remove duplicate RippleAddresses controller actions
- Remove duplicate Users controller actions
- Remove unused files in lib/core and test/core

### Added Features:
- Extract capistrano into https://github.com/gatewayd/gatewayd-capistrano
- Extract docker into https://github.com/gatewayd/gatewayd-docker
- Add Procfile for process management on Heroku and / or with Foreman
- Support currency amount in CLI
- Bridges database table migration and ORM Model
- Add controller actions for gateway_transactions database table
- Refactor CRUD routes for all resources to be DRY
There is an short issue created here: https://github.com/ripple/gatewayd/issues/294 if you would like to elaborate.