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/repository/target/target.go

@@ -5,8 +5,8 @@ import (
 	"time"
 
 	"github.com/zitadel/zitadel/internal/crypto"
-	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/eventstore"
+	target_domain "github.com/zitadel/zitadel/internal/execution/target"
 )
 
 const (
@@ -19,12 +19,12 @@ const (
 type AddedEvent struct {
 	eventstore.BaseEvent `json:"-"`
 
-	Name             string              `json:"name"`
-	TargetType       domain.TargetType   `json:"targetType"`
-	Endpoint         string              `json:"endpoint"`
-	Timeout          time.Duration       `json:"timeout"`
-	InterruptOnError bool                `json:"interruptOnError"`
-	SigningKey       *crypto.CryptoValue `json:"signingKey"`
+	Name             string                   `json:"name"`
+	TargetType       target_domain.TargetType `json:"targetType"`
+	Endpoint         string                   `json:"endpoint"`
+	Timeout          time.Duration            `json:"timeout"`
+	InterruptOnError bool                     `json:"interruptOnError"`
+	SigningKey       *crypto.CryptoValue      `json:"signingKey"`
 }
 
 func (e *AddedEvent) SetBaseEvent(b *eventstore.BaseEvent) {
@@ -43,7 +43,7 @@ func NewAddedEvent(
 	ctx context.Context,
 	aggregate *eventstore.Aggregate,
 	name string,
-	targetType domain.TargetType,
+	targetType target_domain.TargetType,
 	endpoint string,
 	timeout time.Duration,
 	interruptOnError bool,
@@ -59,12 +59,12 @@ func NewAddedEvent(
 type ChangedEvent struct {
 	eventstore.BaseEvent `json:"-"`
 
-	Name             *string             `json:"name,omitempty"`
-	TargetType       *domain.TargetType  `json:"targetType,omitempty"`
-	Endpoint         *string             `json:"endpoint,omitempty"`
-	Timeout          *time.Duration      `json:"timeout,omitempty"`
-	InterruptOnError *bool               `json:"interruptOnError,omitempty"`
-	SigningKey       *crypto.CryptoValue `json:"signingKey,omitempty"`
+	Name             *string                   `json:"name,omitempty"`
+	TargetType       *target_domain.TargetType `json:"targetType,omitempty"`
+	Endpoint         *string                   `json:"endpoint,omitempty"`
+	Timeout          *time.Duration            `json:"timeout,omitempty"`
+	InterruptOnError *bool                     `json:"interruptOnError,omitempty"`
+	SigningKey       *crypto.CryptoValue       `json:"signingKey,omitempty"`
 
 	oldName string
 }
@@ -114,7 +114,7 @@ func ChangeName(oldName, name string) func(event *ChangedEvent) {
 	}
 }
 
-func ChangeTargetType(targetType domain.TargetType) func(event *ChangedEvent) {
+func ChangeTargetType(targetType target_domain.TargetType) func(event *ChangedEvent) {
 	return func(e *ChangedEvent) {
 		e.TargetType = &targetType
 	}