Py-ms

- Changed logging messages to debug
- Added pylint validation to CI

* Fix pypi dependencies

* Access to pyms class from `flask.current_app.ms`

* Added retry system to requests wrapper

* Fix pylint errors

* Updated docs

**Configuration out of context**
Access to our YAML configuration out of Flask context.

See https://py-ms.readthedocs.io/en/latest/configuration/import-configuration for more details

Fix error when Flask search for static files in wrong path