Face-to-face signature and document upload/download

• Signature request can now optionally manage the document to be signed for and easier signature workflow
• Signature workflow can now support face-to-face signature (the requester send an OTP SMS to the signer, the signer communicate back the signature code to the requester, who signs on behalf of the signer using this code)

Woleet Sign

The document to sign can now be optionally uploaded to Woleet by the requester: if so, it is automatically downloaded and verified before being signed.

Core/API

• Fix some issues with Opentimestamp receipts creation
• New endpoints to upload and download the document to sign added
• Faster receipt verification and faster access to bitcoin transactions
• Signature request credits are now consumed only at activation time for stateful signature requests