Add UMUDGA, UTL_DGA22 datasets; move DNS_EXF_TUN to discard; add next/PhishMalware

Update ThreatFox_MalDomains/README.md

Update ThreatFox_MalDomains/README.md

Create README.md

rename label/class values: tunneling->malicious, plain->legit

add DNS_EXF_TUN, Hranicky, ThreatFox_MalDomains datasets

initial commit