Add automatic signing configuration for loan contracts

Summary

This update introduces configuration options in the financial product contract templates to require and automate the signing of loan contracts by a specified signer.

Updated endpoints

• FinancialProductConfiguration
  • The contract_templates property now references a new schema FinancialProductContractTemplate which includes an optional signature_config.

Changes in definitions

• Added AutomaticSigner definition to specify signer details (email, first name, last name, IP address).
• Replaced ContractTemplate with FinancialProductContractTemplate, extending it by adding a nullable signature_config property.
• Added SignatureConfig definition specifying:
  • signing_fields for positioning signature areas on the contract template.
  • automatic_signer for automatic signing by a predefined identity.
  • contract_template_name enum to identify the contract template used.
• Added SigningField to define signature position details including page, position, size, type, and optional mention.

These changes enable financial products to define contract templates that can automatically be signed based on provided configuration, streamlining the loan contract signing workflow.