feat(OIDC): add back channel logout (#8837)

# Which Problems Are Solved

Currently ZITADEL supports RP-initiated logout for clients. Back-channel
logout ensures that user sessions are terminated across all connected
applications, even if the user closes their browser or loses
connectivity providing a more secure alternative for certain use cases.

# How the Problems Are Solved

If the feature is activated and the client used for the authentication
has a back_channel_logout_uri configured, a
`session_logout.back_channel` will be registered. Once a user terminates
their session, a (notification) handler will send a SET (form POST) to
the registered uri containing a logout_token (with the user's ID and
session ID).

- A new feature "back_channel_logout" is added on system and instance
level
- A `back_channel_logout_uri` can be managed on OIDC applications
- Added a `session_logout` aggregate to register and inform about sent
`back_channel` notifications
- Added a `SecurityEventToken` channel and `Form`message type in the
notification handlers
- Added `TriggeredAtOrigin` fields to `HumanSignedOut` and
`TerminateSession` events for notification handling
- Exported various functions and types in the `oidc` package to be able
to reuse for token signing in the back_channel notifier.
- To prevent that current existing session termination events will be
handled, a setup step is added to set the `current_states` for the
`projections.notifications_back_channel_logout` to the current position

- [x] requires https://github.com/zitadel/oidc/pull/671

# Additional Changes

- Updated all OTEL dependencies to v1.29.0, since OIDC already updated
some of them to that version.
- Single Session Termination feature is correctly checked (fixed feature
mapping)

# Additional Context

- closes https://github.com/zitadel/zitadel/issues/8467
- TODO:
  - Documentation
  - UI to be done: https://github.com/zitadel/zitadel/issues/8469

---------

Co-authored-by: Hidde Wieringa <hidde@hiddewieringa.nl>

internal/notification/projections.go

@@ -2,6 +2,7 @@ package notification
 
 import (
 	"context"
+	"time"
 
 	"github.com/zitadel/zitadel/internal/command"
 	"github.com/zitadel/zitadel/internal/crypto"
@@ -17,7 +18,7 @@ var projections []*handler.Handler
 
 func Register(
 	ctx context.Context,
-	userHandlerCustomConfig, quotaHandlerCustomConfig, telemetryHandlerCustomConfig projection.CustomConfig,
+	userHandlerCustomConfig, quotaHandlerCustomConfig, telemetryHandlerCustomConfig, backChannelLogoutHandlerCustomConfig projection.CustomConfig,
 	telemetryCfg handlers.TelemetryPusherConfig,
 	externalDomain string,
 	externalPort uint16,
@@ -25,14 +26,24 @@ func Register(
 	commands *command.Commands,
 	queries *query.Queries,
 	es *eventstore.Eventstore,
-	otpEmailTmpl string,
-	fileSystemPath string,
-	userEncryption, smtpEncryption, smsEncryption crypto.EncryptionAlgorithm,
+	otpEmailTmpl, fileSystemPath string,
+	userEncryption, smtpEncryption, smsEncryption, keysEncryptionAlg crypto.EncryptionAlgorithm,
+	tokenLifetime time.Duration,
 ) {
 	q := handlers.NewNotificationQueries(queries, es, externalDomain, externalPort, externalSecure, fileSystemPath, userEncryption, smtpEncryption, smsEncryption)
 	c := newChannels(q)
 	projections = append(projections, handlers.NewUserNotifier(ctx, projection.ApplyCustomConfig(userHandlerCustomConfig), commands, q, c, otpEmailTmpl))
 	projections = append(projections, handlers.NewQuotaNotifier(ctx, projection.ApplyCustomConfig(quotaHandlerCustomConfig), commands, q, c))
+	projections = append(projections, handlers.NewBackChannelLogoutNotifier(
+		ctx,
+		projection.ApplyCustomConfig(backChannelLogoutHandlerCustomConfig),
+		commands,
+		q,
+		es,
+		keysEncryptionAlg,
+		c,
+		tokenLifetime,
+	))
 	if telemetryCfg.Enabled {
 		projections = append(projections, handlers.NewTelemetryPusher(ctx, telemetryCfg, projection.ApplyCustomConfig(telemetryHandlerCustomConfig), commands, q, c))
 	}