Move github webhook from webapp to zuul-web

We want to have zuul-web to handle all http serving stuff so also the
github webhook handling needs to be moved to zuul-web.

Note that this changes the url of the github webhooks to
/driver/github/<connection_name>/payload.

Change-Id: I6482de6c5b9655ac0b9bf353b37a59cd5406f1b7
Signed-off-by: Jesse Keating <omgjlk@us.ibm.com>
Co-Authored-by: Tobias Henkel <tobias.henkel@bmw.de>
9 files changed