setup custom autoloaders, fixed permissions

Summary:
- fixed permissions from 644 to 755
- setup autoloaders in composer.json
- added empty directories for repositories, providers, extensions
- namespaces existing controllers/models

Test Plan: manual rivision

Reviewers: pwningnoobs

Reviewed By: pwningnoobs

Maniphest Tasks: T2

Differential Revision: http://phab.nickc.io/D1