Ignore invalid routes

[therealak12]

This PR tries to solve the following issue:

When multiple routes have the same FQDN and one or more of them is invalid (e.g. due to a non-existent target service), the controller will discard the whole set of routes.
For example, imagine we have a set of routes like this:

route	FQDN	path	target service exists
route1	example.com	/a	yes
route2	example.com	/b	no
route2	example.com	/c	yes

The openshift router will configure HAProxy so that /a and /c is accessible but the controller will ignore the whole set of routes and no path will be accessible.

The solution is to ignore the invalid routes and continue the reconciliation for other routes. A new problem arises here. If the target service for path /b is later created, we won't be informed. To solve this problem, the PR also adds a watch on Kubernetes Services.