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/query/projection/eventstore_mock_test.go

@@ -0,0 +1,44 @@
+package projection
+
+import (
+	"context"
+	"time"
+
+	"github.com/zitadel/zitadel/internal/eventstore"
+	"github.com/zitadel/zitadel/internal/eventstore/handler/v2"
+)
+
+var _ handler.EventStore = (*mockEventStore)(nil)
+
+type mockEventStore struct {
+	instanceIDsResponse [][]string
+	instanceIDCounter   int
+	filterResponse      [][]eventstore.Event
+	filterCounter       int
+	pushResponse        [][]eventstore.Event
+	pushCounter         int
+}
+
+func newMockEventStore() *mockEventStore {
+	return new(mockEventStore)
+}
+
+func (m *mockEventStore) appendFilterResponse(events []eventstore.Event) *mockEventStore {
+	m.filterResponse = append(m.filterResponse, events)
+	return m
+}
+
+func (m *mockEventStore) InstanceIDs(ctx context.Context, _ time.Duration, _ bool, query *eventstore.SearchQueryBuilder) ([]string, error) {
+	m.instanceIDCounter++
+	return m.instanceIDsResponse[m.instanceIDCounter-1], nil
+}
+
+func (m *mockEventStore) Filter(ctx context.Context, queryFactory *eventstore.SearchQueryBuilder) ([]eventstore.Event, error) {
+	m.filterCounter++
+	return m.filterResponse[m.filterCounter-1], nil
+}
+
+func (m *mockEventStore) Push(ctx context.Context, cmds ...eventstore.Command) ([]eventstore.Event, error) {
+	m.pushCounter++
+	return m.pushResponse[m.pushCounter-1], nil
+}