Stop putting ed25519 link specifiers in v3 onion service descriptors,
when the intro point doesn't support ed25519 link authentication.
Fixes bug 26627; bugfix on 0.3.2.4-alpha.
* 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
- Fix log message format string.
- Do extra circuit purpose check.
- wipe memory in a clear function
- Make sure we don't double add intro points in our list
- Make sure we don't double close intro circuits.
- s/tt_u64_op/tt_i64_op/
