Fix @covers code coverage annotation

delete tests for deploy

Change-Id: I0c0bd581c79dfbef467837fd165b40a3b4547fc3
Move gateway form logic from execute to handleRequest

Move execute method from GatewayForm subclasses into GatewayForm
so it can run global checks before executing gateway-specific logic.
As awight points out, this is a baby step towards separating the mediawiki
stuff from the gateway-specific stuff.

Remove unused page parameters from handleRequest, make GatewayForm
an abstract class and handleRequest and abstract method.

Change-Id: I31d10babc97fe81c34a61124128e66411254bb4c