perf(actionsv2): execution target router (#10564)

# Which Problems Are Solved

The event execution system currently uses a projection handler that
subscribes to and processes all events for all instances. This creates a
high static cost because the system over-fetches event data, handling
many events that are not needed by most instances. This inefficiency is
also reflected in high "rows returned" metrics in the database.

# How the Problems Are Solved

Eliminate the use of a project handler. Instead, events for which
"execution targets" are defined, are directly pushed to the queue by the
eventstore. A Router is populated in the Instance object in the authz
middleware.

- By joining the execution targets to the instance, no additional
queries are needed anymore.
- As part of the instance object, execution targets are now cached as
well.
- Events are queued within the same transaction, giving transactional
guarantees on delivery.
- Uses the "insert many fast` variant of River. Multiple jobs are queued
in a single round-trip to the database.
- Fix compatibility with PostgreSQL 15

# Additional Changes

- The signing key was stored as plain-text in the river job payload in
the DB. This violated our [Secrets
Storage](https://zitadel.com/docs/concepts/architecture/secrets#secrets-storage)
principle. This change removed the field and only uses the encrypted
version of the signing key.
- Fixed the target ordering from descending to ascending.
- Some minor linter warnings on the use of `io.WriteString()`.

# Additional Context

- Introduced in https://github.com/zitadel/zitadel/pull/9249
- Closes https://github.com/zitadel/zitadel/issues/10553
- Closes https://github.com/zitadel/zitadel/issues/9832
- Closes https://github.com/zitadel/zitadel/issues/10372
- Closes https://github.com/zitadel/zitadel/issues/10492

---------

Co-authored-by: Stefan Benz <46600784+stebenz@users.noreply.github.com>
(cherry picked from commit a9ebc06c77)

internal/api/grpc/action/v2beta/target_test.go

@@ -9,7 +9,7 @@ import (
 	"google.golang.org/protobuf/types/known/durationpb"
 
 	"github.com/zitadel/zitadel/internal/command"
-	"github.com/zitadel/zitadel/internal/domain"
+	target_domain "github.com/zitadel/zitadel/internal/execution/target"
 	action "github.com/zitadel/zitadel/pkg/grpc/action/v2beta"
 )
 
@@ -44,7 +44,7 @@ func Test_createTargetToCommand(t *testing.T) {
 			}},
 			want: &command.AddTarget{
 				Name:             "target 1",
-				TargetType:       domain.TargetTypeWebhook,
+				TargetType:       target_domain.TargetTypeWebhook,
 				Endpoint:         "https://example.com/hooks/1",
 				Timeout:          10 * time.Second,
 				InterruptOnError: false,
@@ -62,7 +62,7 @@ func Test_createTargetToCommand(t *testing.T) {
 			}},
 			want: &command.AddTarget{
 				Name:             "target 1",
-				TargetType:       domain.TargetTypeAsync,
+				TargetType:       target_domain.TargetTypeAsync,
 				Endpoint:         "https://example.com/hooks/1",
 				Timeout:          10 * time.Second,
 				InterruptOnError: false,
@@ -82,7 +82,7 @@ func Test_createTargetToCommand(t *testing.T) {
 			}},
 			want: &command.AddTarget{
 				Name:             "target 1",
-				TargetType:       domain.TargetTypeCall,
+				TargetType:       target_domain.TargetTypeCall,
 				Endpoint:         "https://example.com/hooks/1",
 				Timeout:          10 * time.Second,
 				InterruptOnError: true,
@@ -155,7 +155,7 @@ func Test_updateTargetToCommand(t *testing.T) {
 			}},
 			want: &command.ChangeTarget{
 				Name:             gu.Ptr("target 1"),
-				TargetType:       gu.Ptr(domain.TargetTypeWebhook),
+				TargetType:       gu.Ptr(target_domain.TargetTypeWebhook),
 				Endpoint:         gu.Ptr("https://example.com/hooks/1"),
 				Timeout:          gu.Ptr(10 * time.Second),
 				InterruptOnError: gu.Ptr(false),
@@ -175,7 +175,7 @@ func Test_updateTargetToCommand(t *testing.T) {
 			}},
 			want: &command.ChangeTarget{
 				Name:             gu.Ptr("target 1"),
-				TargetType:       gu.Ptr(domain.TargetTypeWebhook),
+				TargetType:       gu.Ptr(target_domain.TargetTypeWebhook),
 				Endpoint:         gu.Ptr("https://example.com/hooks/1"),
 				Timeout:          gu.Ptr(10 * time.Second),
 				InterruptOnError: gu.Ptr(true),
@@ -193,7 +193,7 @@ func Test_updateTargetToCommand(t *testing.T) {
 			}},
 			want: &command.ChangeTarget{
 				Name:             gu.Ptr("target 1"),
-				TargetType:       gu.Ptr(domain.TargetTypeAsync),
+				TargetType:       gu.Ptr(target_domain.TargetTypeAsync),
 				Endpoint:         gu.Ptr("https://example.com/hooks/1"),
 				Timeout:          gu.Ptr(10 * time.Second),
 				InterruptOnError: gu.Ptr(false),
@@ -213,7 +213,7 @@ func Test_updateTargetToCommand(t *testing.T) {
 			}},
 			want: &command.ChangeTarget{
 				Name:             gu.Ptr("target 1"),
-				TargetType:       gu.Ptr(domain.TargetTypeCall),
+				TargetType:       gu.Ptr(target_domain.TargetTypeCall),
 				Endpoint:         gu.Ptr("https://example.com/hooks/1"),
 				Timeout:          gu.Ptr(10 * time.Second),
 				InterruptOnError: gu.Ptr(true),