Support the injection of AccessTokenCredential and IdTokenCredential

[sberyozkin]

Description
Let users do

@Inject
AccessTokenCredential at;

instead of

@Inject
SecurityIdentity identity;
...
AccessTokenCredential at = identity.getTokenCredential(AccessTokenCredential.class);

and the same for IdTokenCredential.

A bit simpler when nothing else is required from SecurityIdentity.
(Based on Pedro's idea to inject refresh tokens as token creds)

Implementation ideas
Add a simple producer