create npm workspace for monorepo

[EzraBrooks]

Creates a root-level package.json that lets us run ci/install, build and test on all packages in the repo with one command.

[drewhoener]

Out of curiousity (since the topic is open), have you considered pnpm for the project? It has some nice features to build off of base npm workspaces and is usually a drop-in replacement.
You get some better checks from the stricter dependency management and it's good about deduplicating packages in node_modules, which for a monorepo can save a lot on space

[EzraBrooks]

PNPM is my package manager of choice, yes. My current plan is to gather up all the robotwebtools JS libraries, which are NPM projects, into a monorepo, and then convert it to PNPM all at once afterward