did:ion and DID operations

[clehner]

Integrate Sidetree/ION implementation and DID operations from spruceid/ssi#379.

• Add did:ion method/resolver
• Add generate-secp256k1-key command
• Add create command
• Submit operations to Sidetree/ION API
• Add update command
• Add recover command
• Add deactivate command
• Update readme to document new commands

Example Usage

# Generate initial keys
$ didkit generate-secp256k1-key > update0.jwk
$ didkit generate-secp256k1-key > recovery0.jwk
$ didkit generate-secp256k1-key > signing0.jwk

# Create DID
$ did=$(didkit did-create ion -r recovery0.jwk -u update0.jwk -s signing0.jwk)

# Resolve long-form DID
$ DID_ION_API_URL=http://localhost:3000/ didkit did-resolve "$did"

[sbihel]

Do you think you will move to subcommands before merging?

[clehner]

@sbihel I don't think so, unless there is a straightforward way to do it

[clehner]

Opened #266 about the CLI

[clehner]

Rebased and merged.
Docker image publish failed because ssi@main updated to v0.4 while didkit is not yet ready for ssi v0.4: https://github.com/spruceid/didkit/runs/5398417705?check_suite_focus=true
spruceid/ssi#401 should have been merged after this PR for that workflow to have succeeded. This will be fixed when didkit is updated to use ssi v0.4 (#269).