adopt C_EncodingUtil perhaps

[emptyrivers]

some notes:

• not yet available on all game flavors, because blizzard hates fun
• substantially faster than LibDeflate+LibSerialize for what seem like obvious reasons
• base64 encoding of LibDeflate is nonstandard (it cribs a very old utility from us in fact), but blizzard adheres to rfc 4648 (maybe we can just gsub () to +/ & not have to lug around LibDeflate??)
• LibSerialize is a bespoke format that's not compatible with either CBOR or JSON, unfortunately. so old strings still need the embed
• archivist strings use yet another serialize format, at least on version 1 which is what weakauras consumes. version 2 employs LibDeflate & LibSerialize, the soon-to-be version 3 employs C_EncodingUtil directly
• adoption isn't super pressing since "import auras" is for most users a "once per season when causese dungeon auras update" kind of thing
  • but wait, there's more! aura_env.saved strings might have a bigger effect on normal gameplay. thankfully no custom coded aura exists which uses that feature for more than a few dozen byte, though. r-right?