feat(eventstore): increase parallel write capabilities (#5940)

This implementation increases parallel write capabilities of the eventstore.
Please have a look at the technical advisories: [05](https://zitadel.com/docs/support/advisory/a10005) and  [06](https://zitadel.com/docs/support/advisory/a10006).
The implementation of eventstore.push is rewritten and stored events are migrated to a new table `eventstore.events2`.
If you are using cockroach: make sure that the database user of ZITADEL has `VIEWACTIVITY` grant. This is used to query events.

internal/notification/handlers/ctx.go

@@ -9,7 +9,7 @@ import (
 
 const NotifyUserID = "NOTIFICATION" //TODO: system?
 
-func HandlerContext(event eventstore.Aggregate) context.Context {
+func HandlerContext(event *eventstore.Aggregate) context.Context {
 	ctx := authz.WithInstanceID(context.Background(), event.InstanceID)
 	return authz.SetCtxData(ctx, authz.CtxData{UserID: NotifyUserID, OrgID: event.ResourceOwner})
 }