Attesteer API for requesting remote attestation

[clangenb]

So far we have only implemented the PoC for the Attesteer such that it can fetch the Marbles of Marblerun and fetch the enclave quote to send a remote attestation on chain. However, for non-security setups, we need to expose an endpoint to request forwarding of a remote attestation. This should be fairly simple:

• Add RPC method to the trusted TLS server to request forwarding. One for IAS and one for DCAP.
• We also need to check f the requester has subscribed to using the service. We will probably have a pro-rata billig, so we need a local DB that stores per subscriber: 1. Remaining quota, 2. How many requests have been sent. Not sure about the second though, all the remote attestations are already on the public blockchain.

[clangenb]

Should we consider that this could also be a pull service?

[clangenb]

So summarizing about what we talked about: The Attesteer shall be used by clients who do not use our SDK; hence we should not use the TrustedOperation in the RPC, which will also remove the double encryption issue for this specific RPC. Steps to do:

1. Add two commands here: https://github.com/integritee-network/worker/tree/b900e2da99c3d766a2adddd7b2bfb5f46c105f29/cli/src, in a new module attesteer similar to evm and oracle.
   Todo: in what format is it the easiest to supply the attestation to the CLI (hex, json)? in a first step, we could also read it from the file system if we have one available/or even hardcode it. -> Go for the quickest solution here, and refine later.
   • send_ias_attestation,
   • send_dcap_quote
2. Let yourself inspire from send_request:

   worker/cli/src/trusted_operation.rs

   Line 105 in d71d2c5

   fn send_request(

   • but don't send an encrypted trusted operation, send and hex-encoded, unencrypted quote/attestation report
   • the result is not a trusted operation status, but simply an ok/error.
3. Skip decrypting the rpc-params here, as you receive the quote directly:

   worker/enclave-runtime/src/rpc/worker_api_direct.rs

   Line 252 in b900e2d

   let request =