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/query/projection/app.go

@@ -58,6 +58,7 @@ const (
 	AppOIDCConfigColumnClockSkew                = "clock_skew"
 	AppOIDCConfigColumnAdditionalOrigins        = "additional_origins"
 	AppOIDCConfigColumnSkipNativeAppSuccessPage = "skip_native_app_success_page"
+	AppOIDCConfigColumnBackChannelLogoutURI     = "back_channel_logout_uri"
 
 	appSAMLTableSuffix             = "saml_configs"
 	AppSAMLConfigColumnAppID       = "app_id"
@@ -125,6 +126,7 @@ func (*appProjection) Init() *old_handler.Check {
 			handler.NewColumn(AppOIDCConfigColumnClockSkew, handler.ColumnTypeInt64, handler.Default(0)),
 			handler.NewColumn(AppOIDCConfigColumnAdditionalOrigins, handler.ColumnTypeTextArray, handler.Nullable()),
 			handler.NewColumn(AppOIDCConfigColumnSkipNativeAppSuccessPage, handler.ColumnTypeBool, handler.Default(false)),
+			handler.NewColumn(AppOIDCConfigColumnBackChannelLogoutURI, handler.ColumnTypeText, handler.Nullable()),
 		},
 			handler.NewPrimaryKey(AppOIDCConfigColumnInstanceID, AppOIDCConfigColumnAppID),
 			appOIDCTableSuffix,
@@ -500,6 +502,7 @@ func (p *appProjection) reduceOIDCConfigAdded(event eventstore.Event) (*handler.
 				handler.NewCol(AppOIDCConfigColumnClockSkew, e.ClockSkew),
 				handler.NewCol(AppOIDCConfigColumnAdditionalOrigins, database.TextArray[string](e.AdditionalOrigins)),
 				handler.NewCol(AppOIDCConfigColumnSkipNativeAppSuccessPage, e.SkipNativeAppSuccessPage),
+				handler.NewCol(AppOIDCConfigColumnBackChannelLogoutURI, e.BackChannelLogoutURI),
 			},
 			handler.WithTableSuffix(appOIDCTableSuffix),
 		),
@@ -522,7 +525,7 @@ func (p *appProjection) reduceOIDCConfigChanged(event eventstore.Event) (*handle
 		return nil, zerrors.ThrowInvalidArgumentf(nil, "HANDL-GNHU1", "reduce.wrong.event.type %s", project.OIDCConfigChangedType)
 	}
 
-	cols := make([]handler.Column, 0, 15)
+	cols := make([]handler.Column, 0, 16)
 	if e.Version != nil {
 		cols = append(cols, handler.NewCol(AppOIDCConfigColumnVersion, *e.Version))
 	}
@@ -568,6 +571,9 @@ func (p *appProjection) reduceOIDCConfigChanged(event eventstore.Event) (*handle
 	if e.SkipNativeAppSuccessPage != nil {
 		cols = append(cols, handler.NewCol(AppOIDCConfigColumnSkipNativeAppSuccessPage, *e.SkipNativeAppSuccessPage))
 	}
+	if e.BackChannelLogoutURI != nil {
+		cols = append(cols, handler.NewCol(AppOIDCConfigColumnBackChannelLogoutURI, *e.BackChannelLogoutURI))
+	}
 
 	if len(cols) == 0 {
 		return handler.NewNoOpStatement(e), nil