enterprise/stages: Add MTLS stage (#14296)

* prepare client auth with inbuilt server

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

* introduce better IPC auth

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

* init

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

* start stage

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

* only allow trusted proxies to set MTLS headers

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

* more stage progress

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

* dont fail if ipc_key doesn't exist

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

* actually install app

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

* fix

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

* add some tests

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

* update API

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

* fix unquote

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

* fix int serial number not jsonable

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

* init ui

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

* add UI

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

* unrelated: fix git pull in makefile

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

* fix parse helper

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

* add test for outpost

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

* more tests and improvements

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

* improve labels

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

* add support for multiple CAs on brand

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

* add support for multiple CAs to MTLS stage

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

* dont log ipcuser secret views

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

* fix go mod

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

---------

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

internal/outpost/ak/api.go

@@ -62,7 +62,7 @@ func NewAPIController(akURL url.URL, token string) *APIController {
 	apiConfig.Scheme = akURL.Scheme
 	apiConfig.HTTPClient = &http.Client{
 		Transport: web.NewUserAgentTransport(
-			constants.OutpostUserAgent(),
+			constants.UserAgentOutpost(),
 			web.NewTracingTransport(
 				rsp.Context(),
 				GetTLSTransport(),