[th/platform-no-bpf-filter-route] Revert "platform: add bpf filter to ignore routes from routing daemons"

The BPF filter from commit e9ca5583 causes problems: https://bugzilla.redhat.com/show_bug.cgi?id=2037411

Remove it, and filter out the routes in user-space.

This regresses the original performance issue that the BPF filter was supposed to address. That problem is only partly solved, because we now filter in user space (which is expected to have higher overhead). Doing this in user space may (or may not) be good enough. In any case, this requires fresh profiling and possibly find a better solution.

What the branch does, it preserves the behavior of ignoring certain routes. We probably want to stick to that, because we cannot cache hundred of thousands of routes anyway. Keeping that behavior (even if not the full performance benefits) is important for now, to test how this fares and gather experience.