Add/Delete API keys to Service accounts (#44871)

* ServiceAccounts: move token handlers to specific file

* ServiceAccounts: move Add API key to Service account

* APIKeys: api keys can still be used even when service accounts are enabled

* APIKeys: legacy endpoint can't be used to add SA tokens

* ServiceAccount: add tests for creation with nil and non-nil service account ids

* ServiceAccounts: fix unnasigned cfg and AC typo

* Test: test service account token adding

* fix linting error

* ServiceAccounts: Handle Token deletion

* rename token funcs

* rename token funcs and api wrapping

* add token deletion tests

* review

Co-authored-by: eleijonmarck <eric.leijonmarck@gmail.com>

* remove bus

* Update pkg/api/apikey.go

Co-authored-by: eleijonmarck <eric.leijonmarck@gmail.com>

pkg/models/apikey.go

@@ -21,7 +21,7 @@ type ApiKey struct {
 	Created          time.Time
 	Updated          time.Time
 	Expires          *int64
-	ServiceAccountId int64
+	ServiceAccountId *int64
 }
 
 // ---------------------
@@ -32,7 +32,7 @@ type AddApiKeyCommand struct {
 	OrgId            int64    `json:"-"`
 	Key              string   `json:"-"`
 	SecondsToLive    int64    `json:"secondsToLive"`
-	ServiceAccountId int64    `json:"-"`
+	ServiceAccountId *int64   `json:"-"`
 	Result           *ApiKey  `json:"-"`
 }