promote and pedpop require dleq, which don't support no-std. All three should
be moved outside the Serai repository, per #597, as none are planned for use
and worth covering under our BBP.
common/ is now only run when common is edited. crypto/ when common/ or crypto/.
coins/ when common/ or crypto/ or coins/. The rest of the tests are run
whenever any package is edited (as they're all inter-connected).