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/repository/milestone/events.go

@@ -11,6 +11,8 @@ const (
 	PushedEventType = eventTypePrefix + "pushed"
 )
 
+var _ eventstore.Command = (*PushedEvent)(nil)
+
 type PushedEvent struct {
 	*eventstore.BaseEvent `json:"-"`
 	MilestoneType         Type     `json:"type"`
@@ -19,11 +21,12 @@ type PushedEvent struct {
 	Endpoints             []string `json:"endpoints"`
 }
 
-func (p *PushedEvent) Data() interface{} {
+// Payload implements eventstore.Command.
+func (p *PushedEvent) Payload() any {
 	return p
 }
 
-func (p *PushedEvent) UniqueConstraints() []*eventstore.EventUniqueConstraint {
+func (p *PushedEvent) UniqueConstraints() []*eventstore.UniqueConstraint {
 	return nil
 }