providers/proxy: outpost wide logout implementation (#4605)

* initial outpost wide logout implementation

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

* handle deserialize error

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

* update docs

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

* fix file cleanup, add tests

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

* fix tests

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

---------

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

internal/outpost/proxyv2/application/test.go

@@ -3,7 +3,6 @@ package application
 import (
 	"net/http"
 
-	"github.com/quasoft/memstore"
 	"goauthentik.io/api/v3"
 	"goauthentik.io/internal/outpost/ak"
 )
@@ -41,8 +40,5 @@ func newTestApplication() *Application {
 			ak.MockConfig(),
 		),
 	)
-	a.sessions = memstore.NewMemStore(
-		[]byte(ak.TestSecret()),
-	)
 	return a
 }