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/eventstore/v3/sequences_query.sql

@@ -0,0 +1,30 @@
+with existing as (
+    SELECT
+        instance_id
+        , aggregate_type
+        , aggregate_id
+        , MAX("sequence") "sequence"
+    FROM 
+        eventstore.events2 existing
+    WHERE 
+        %s
+    GROUP BY 
+        instance_id
+        , aggregate_type
+        , aggregate_id
+) SELECT 
+    e.instance_id
+    , e.owner
+    , e.aggregate_type
+    , e.aggregate_id
+    , e.sequence
+FROM 
+    eventstore.events2 e
+JOIN 
+    existing 
+ON 
+        e.instance_id = existing.instance_id
+        AND e.aggregate_type = existing.aggregate_type
+        AND e.aggregate_id = existing.aggregate_id
+        AND e.sequence = existing.sequence
+FOR UPDATE;