Revert route change PR

[driesvints]

Reverts:

• [9.x] Use model route key when route parameter does not specifiy custom binding field but a different parameter does #42425
• [9.x] Fix regression when only some route parameters are scoped #42517
• [9.x] Map integer parameter to parameter name when resolving binding field #42571

Brings back the way to how things worked before these PR's. I left the test by Kai in place so we can fix that some day.