Services

Summary:
Several classes implemented some methods to query credentials.json file.

We create a Services class to move and generalize these methods into.

Test Plan:
Same as D157

• php artisan phabricator:projectsmap
• Test a GitHub payload request
• Test a Phabricator payload request

Reviewers: dereckson

Differential Revision: http://devcentral.nasqueron.org/D160