refactor: optimize v0.50.0 release (#975)

- Simplifies architecture for splitting engine services into different components. The three supported services are now `grpc-api`, `scheduler`, and `controllers`. The `grpc-api` service is the only one which needs to be exposed for workers. The other two can run as unexposed services.
- Fixes a set of bugs and race conditions in the `v2` scheduler
- Adds a `lastActive` time to the `Queue` table and includes a migration which sets this `lastActive` time for the most recent 24 hours of queues. Effectively this means that the max scheduling time in a queue is 24 hours. 
- Rewrites the `ListWorkflowsForEvent` query to improve performance and select far fewer rows.

internal/msgqueue/msgqueue.go

@@ -98,6 +98,7 @@ func QueueTypeFromTickerID(t string) consumerQueue {
 const (
 	JobController      = "job"
 	WorkflowController = "workflow"
+	Scheduler          = "scheduler"
 )
 
 func QueueTypeFromPartitionIDAndController(p, controller string) consumerQueue {