Update package setup

[freeatnet]

This PR updates the package setup with the goal of getting the package setup to work on Node 18 / npm v9.

Originally, I set out to investigate a CI failure on spruceid/siwe@main and found that the file: protocol dependencies specified in the root package.json were breaking with Node 18 and npm v9. While debugging the issue, I found that the current state of the package.json file could use some overall cleanup.

In sum total, this PR:

• Converts the root package.json to use the workspaces directive and cleans up directives left over from before siwe became a monorepo.
• Upgrades lerna to v6, with the most notable change being the deprecation of lerna bootstrap.
• Adds Node 16 and 18 testing in ci.yaml, also upgrading to actions/checkout@v3.

[w4ll3]

Changes looks good. Will be performing some test to make sure nothing is broken.

[freeatnet]

@w4ll3 rebased to resolve conflicts, let me know if anything else needs attention

[w4ll3]

Hi there, sorry for the delay here. Could you push a commit to trigger the CI? Getting the green mark I'll merge this.

[freeatnet]

@w4ll3 done