[Secret NFTs] Shamir Secret Sharing + SGX Enclaves

[ipapandinas]

Atomic helpers

• [x] generateSSSShares(privateKey)
• [x] getSgxEnclaves()* => return enclaves url
• [x] getSignature(keyring, data)** => u8aToHex(sender.sign(data))
• [x] sgxSSSSharesUpload ()***^

*Hardcoded first, in the future query chain storage to discover enclaves *data = nftId + accountAddress + sssaShare **POST request on /save endpoint with sgx_data = JSON.stringify({ data, signature }) \^provide some information about the upload progress state

Additionnal work

• [x] explore a no keyring flow
• [x] compatibility: frontend / backend / react-native