UTF-8 support added to FString::AppendChars() and made able to correctly handle variably-encoded source strings (both wider and narrower than TCHAR).
FUTF8ToTCHAR now accepts either UTF8CHAR* or ANSICHAR* for better compatibility.
FUtf8StringView now binds to UTF8CHAR* or any UTF8CHAR range, and can be constructed via a _U8SV string literal suffix.
CompactBinary now supports UTF-8.
Miscellaneous other UTF8CHAR fixes.
#rb devin.doucette
[CL 17017066 by Steve Robb in ue5-main branch]