[V2] Use new configuration system

[LoicPoullain]

Issue

Resolves #805
Resolves #497

Solution and steps

• Add Env class.
• Re-implement Config class.
• Upgrade all test in the framework

New features & Breaking changes

mongodb.uri -> settings.mongodb.uri
redis.uri -> settings.redis.uri
settings.jwt.cookieName -> settings.jwt.cookie.name

See also the description of both issues.

Checklist

• Add/update/check docs (code comments and docs/ folder).
• Add/update/check tests.
• Update/check the cli generators.