move core eval scripts out of proposals

[turadg]

What is the Problem Being Solved?

They are used in the creation of proposals but they aren't proposals themselves. #9468 clarifies the difference.

Description of the Design

Change the package/src/proposals pattern to something else.

• src/core - this works for some packages but vats/src/core already means something else
• src/evals - workable but makes it seem like these primary code and part of the semver of the package
• tools/evals - relegates them to tools which is a little less strict
• evals - do they ever need to get out to NPM? maybe we can retain the package home for organization but do the actual building just by filesystem paths

Security Considerations

Scaling Considerations

Test Plan

Upgrade Considerations