Rewrite build/setup and hopefully fix ESM compat

[markerikson]

This PR:

• Switches the build setup from Babel+Rollup to https://github.com/egoist/tsup (an ESBuild wrapper)
• Updates the package formatting to hopefully fix CJS/ESM compat issues
• Moves the build/publish output to all be in ./dist/, and changes the file locations/names
• Drops the UMD bundles from the output
• Copies over the "test published artifact in these example projects" config from RTK and redux-thunk
• Updates the GH Actions test workflow to ignore FalseCJS problems from arethetypeswrong

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