Support COSE_Sign

[ko-isobe]

From ietf-teep/teep-protocol#251

Since teep-protocol-11, TAM can use COSE_Sign for supporting difference algorithm signatures in a single QueryRequest message.
TAM are required to support two MTI signature algorithms; ECDSA(ES256) and EdDSA.
Therefore, tamproto should support both algorithms and multiple signatures in QueryRequest.

The current tamproto depends on cose-js in COSE signing.
cose-js doesn't support COSE_Sign.

There are two options:

• extend cose-js to support COSE_Sign
• use an alternative COSE library.

[ko-isobe]

The 1st option was choosed.

I forked cose-js and added COSE_Sign.
In cose_sign branch, tamproto uses my cose-js and supports COSE_Sign in QueryRequest. 524478d