tools: replace rollup with ncc

Replace rollup + plugins + config file with zeit/ncc package designed to
do the particular task that we're leveraging rollup for but with
zero-ish configuration. (rollup can do a whole lot more, but we're using
a tiny portion of its functionality.)

PR-URL: #24813
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Backport-PR-URL: #28736

Author: Trott