add /api/rbac/context + /api/hs/accounts/current endpoints (#189)

Co-authored-by: Michael Hoennig <michael@hoennig.de>
Reviewed-on: https://dev.hostsharing.net/hostsharing/hs.hsadmin.ng/pulls/189
Reviewed-by: Marc Sandlus <marc.sandlus@hostsharing.net>

src/main/resources/api-definition/rbac/rbac.yaml

@@ -8,6 +8,9 @@ servers:
 
 paths:
 
+    /api/rbac/context:
+        $ref: 'rbac-context.yaml'
+
     /api/rbac/subjects:
         $ref: 'rbac-subjects.yaml'