Enhanced the `AuthController` to support JWT token generation
for `EnvelopeReceiverSecretDto` entities. Added a new
dependency `IJwtSignatureHandler<EnvelopeReceiverSecretDto>`
and updated the constructor to inject it.
Refactored the `CreateTokenForEnvelopeReceiver` method:
- Added a `cookie` query parameter to control token delivery.
- Implemented consumer validation using `_consumerService`.
- Added token descriptor retrieval from `_keyPool`.
- Improved `AccessCode` validation for `EnvelopeReceiver`.
- Added logic to set tokens as cookies or return in the body.
Updated `using` directives to include required namespaces.
Improved error handling, readability, and flexibility in
token generation and delivery.