Export Logs into CloudWatch

[noxdafox]

For the v1 roadmap, the plan is to add logs exporting into CloudWatch as well.

To do so, we need to first develop a Lager backend for CloudWatch, then we can add it as a dependency to the plugin.

The plugin itself would simply take care of correctly configure the CW lager backend for the User.

• [x] Add log group and stream creation to erlcloud (PR #643)
• [x] Develop Lager backend for CloudWatch (https://github.com/noxdafox/lager_cloudwatch)
• [x] Integrate Lager backend into the plugin

[noxdafox]

Feature added in release v1.0.0.