OR-873 Expose web server middlewares as Awesome Modules

Module names are middleware file names, prefixed with linagora.esn.core.webserver.middleware
Merge pull request #608 in OR/rse from ~MBAILLY/rse:OR-873-expose-middlewares-as-modules to master

* commit '34bea6cd306095adaec0e30865bb928faf421659':
  OR-873 Expose web server middlewares as Awesome Modules