util.hashes: Add SHA3 bindings

util.hashes: Bind BLAKE2 algoritms supported by OpenSSL

util.hashes: Refactor PBKDF2 to deduplicate code

util.hashes: Expose sha224 and sha384 HMAC functions For completeness and consistency with set of plain hash functions

util.hashes: Refactor HMAC bindings (fixes #1589) HMAC() is deprecated As with the regular hash functions, macros like this make it awkward to apply static analysis and code formatting.

util.hashes: Refactor hash functions to use OpenSSL EVP methods (fix #1698) MD5() is deprecated, but EVP_md5() is not. Functions in macros like this make it awkward to apply static analysis and code formatting.

Merge 0.12->trunk

net.unbound: Merge luaunbound and prosody defaults in absence of user config (fixes #1763) (thanks rgd) add_defaults() is supposed to merge 3 tables, the defaults in luaunbound, the defaults from prosody and any config from the prosody config file. In the case where no `unbound={}` has been in the config, it skips over the merge and returns only the prosody built-in defaults. This results in libunbound skipping reading resolv.conf and uses its default behavior of full recursive resolution. Prior to #1737 there were only two tables, the luaunbound defaults and the prosody config, where bypassing the merge and returning the former did the right thing.

mod_mam: Silence luacheck (yay warnings in CI but not locally)

mod_mam: Clarify comment (thanks chili-b) This was slightly inaccurate since 6e1af07921d1 because the conditions are more complicated now.