BAC-2718 : Update gem to accept custom service name and timestamp

## Features
- Use custom name service
- Use specific access_key_id, secret_key and region
- Use timestamp instead of date (to use same date everywhere)
- Improve debug mode
- Add some comments

## Jira
https://ifeelgoods.atlassian.net/browse/BAC-2718
:+1 for the extra documentation