Create new function and route to send contract signed email to recipient and user

[Boluwatife Oluwaseyi Abiola]

Why?

• After signing a contract, it takes a while for the content and the signature to be combined, and so it times out
• To fix this (v1), we can probably send the email after the contract and signature has been successfully signed, and when activity logger is done, plus event firing, we can have a faster workflow