GEP: Drop extension points from Route matches

[hbagdi]

What would you like to be added:

This GEP will add a formal prosposal to drop match extension points from all route types within the API.

Why this is needed:

Although these extension points have been present from early days of the API, they are not understood clearly - we do not have concrete use-cases for them and we do not have any feedback on them. We should drop these and introduce them back into the API when we have more clarity.

/kind gep