Split roadmap into phases; add recent additions

[GeoffreyBooth]

I added @cspotcode’s suggestions from nodejs/node#43818 (comment) to our roadmap, and split the roadmap into two phases: the first which is for ESM to achieve parity with CommonJS, and the second is for everything else 😄

1. Is there anything I’m missing from this list?
2. Is there anything that’s under the wrong heading (something in the second phase that is required for parity with CommonJS, or something in the first phase that isn’t required for parity with CommonJS)?

Also, I added finishing --experimental-vm-modules to this list because it comes up as one of the missing pieces in ESM; it’s the biggest thing holding Jest back, for instance. But I wonder how essential it is? I understand that the Jest team surely would prefer not to refactor away from using vm under the hood, but Vitest seems to support most (almost all?) of Jest’s API and claims full ESM support. Are improvements to vm truly needed for ESM to achieve parity with CommonJS? “Parity” here being defined as the capabilities end users have access to once package authors refactor, to swap out one API for another (just as they had to use loader hooks instead of require.extensions).