feat: add debug events API (#8533)

# Which Problems Are Solved

Add a debug API which allows pushing a set of events to be reduced in a
dedicated projection.
The events can carry a sleep duration which simulates a slow query
during projection handling.

# How the Problems Are Solved

- `CreateDebugEvents` allows pushing multiple events which simulate the
lifecycle of a resource. Each event has a `projectionSleep` field, which
issues a `pg_sleep()` statement query in the projection handler :
  - Add
  - Change
  - Remove
- `ListDebugEventsStates` list the current state of the projection,
optionally with a Trigger
- `GetDebugEventsStateByID` get the current state of the aggregate ID in
the projection, optionally with a Trigger


# Additional Changes

- none

# Additional Context

-  Allows reproduction of https://github.com/zitadel/zitadel/issues/8517

internal/query/projection/projection.go

@@ -79,6 +79,7 @@ var (
 	ExecutionProjection                 *handler.Handler
 	UserSchemaProjection                *handler.Handler
 	WebKeyProjection                    *handler.Handler
+	DebugEventsProjection               *handler.Handler
 
 	ProjectGrantFields      *handler.FieldHandler
 	OrgDomainVerifiedFields *handler.FieldHandler
@@ -165,6 +166,7 @@ func Create(ctx context.Context, sqlClient *database.DB, es handler.EventStore,
 	ExecutionProjection = newExecutionProjection(ctx, applyCustomConfig(projectionConfig, config.Customizations["executions"]))
 	UserSchemaProjection = newUserSchemaProjection(ctx, applyCustomConfig(projectionConfig, config.Customizations["user_schemas"]))
 	WebKeyProjection = newWebKeyProjection(ctx, applyCustomConfig(projectionConfig, config.Customizations["web_keys"]))
+	DebugEventsProjection = newDebugEventsProjection(ctx, applyCustomConfig(projectionConfig, config.Customizations["debug_events"]))
 
 	ProjectGrantFields = newFillProjectGrantFields(applyCustomConfig(projectionConfig, config.Customizations[fieldsProjectGrant]))
 	OrgDomainVerifiedFields = newFillOrgDomainVerifiedFields(applyCustomConfig(projectionConfig, config.Customizations[fieldsOrgDomainVerified]))
@@ -295,5 +297,6 @@ func newProjectionsList() {
 		ExecutionProjection,
 		UserSchemaProjection,
 		WebKeyProjection,
+		DebugEventsProjection,
 	}
 }