Create a separate handler for each attribute route

[rynowak]

Right now we have a big global action selection table that includes all actions. This table is largely moot because attribute routes have their own selection criteria. We can solve this by using a per-route-entry handler.

This will also allow us to remove the 'fixup' code from the handler that adjusts the route values.

[Eilon]

@ajaybhargavb please discuss with @rynowak regarding the approach for this.

@rynowak, reminder to ping @davidfowl to discuss this as well.

[rynowak]

2e2784a

[Eilon]

@rynowak close?