Updated what I could, dropped what was easy to remove or no longer needed.

• event-target-shim was added 4 years ago so the treemap app could use AbortController w/ EventTarget. I think support is widely available now, so removing
• node-fetch is not needed
• updated concurrently, which now supports Windows, so also remove npm-run-posix-or-windows
• removed direct dependency on rollup (we just use a rollup plugin for something hacky, but that does not need rollup core)
• removed cross-env, we aren't using it
• updated various packages