This is temporary, until src/or is split.
Putting this in containers would be another logical alternative,
except that addresses depend on containers, and we don't like
cycles.
* ADD new /src/common/crypto_rand.[ch] module.
* ADD new /src/common/crypto_util.[ch] module (contains the memwipe()
function, since all crypto_* modules need this).
* FIXES part of #24658: https://bugs.torproject.org/24658