Use jwt block for signing

[johakoch]

In order to simplify local JWT handling (create/sign and check), it should be possible to also reference jwt blocks from the jwt_sign() function.

To do this, we need

• signing_ttl and
• for RSA keys signing_key/signing_key_file.

So, for JWT signed with an HS256 key

jwt_signing_profile "local_jwt" {
  signature_algorithm = "HS256"
  key = env.LOCAL_JWT_KEY
  ttl = "1h"
}
jwt "local_jwt" {
  signature_algorithm = "HS256"
  key = env.LOCAL_JWT_KEY
  cookie = "local_token"
}

could be simplified to

jwt "local_jwt" {
  signature_algorithm = "HS256"
  key = env.LOCAL_JWT_KEY
  cookie = "local_token"
  signing_ttl = "1h"
}

[alex-schneider]

Type duration, see line 294