During the Host warmup, warmup all WebHost services

Today as part of the `admin/warmup` call, we make sure the Host is running, and then execute any "WarmupTrigger" that may be present.

We should be warming up all the middlewares and WebHost level services to make sure the Runtime is fully warmed up for any new requests.

At the least, we need to investigate and see what type of perf impact we get without actual warmup.

cc: @safihamid, @wenhzha

Start at the admin/warmup entry point and trace the existing Host-start and WarmupTrigger flow. Identify which middleware and WebHost-level services are not warmed, measure the performance impact of leaving them cold, and verify that the runtime is fully warmed for new requests.

Written by the indexing model from the issue text.