Document parallel pentest & golden-ticket credential extraction features

[netanelcyber]

Context

Two significant features shipped without landing docs in the main README.md:

1. Parallel penetration testing — --pentest-technique, --pentest-workers, 5 techniques (SMB null session, LDAP anonymous bind, RPC probe, SMTP VRFY, Kerberos probe)
2. Golden-ticket + credential extraction chain — auto_obtain_golden_ticket() now integrates null-session NTDS dump, DCSync/DRSUAPI, and LDAP unicodePwd fallback

Standalone guides exist (PARALLEL_PENTEST_GUIDE.md, GOLDEN_TICKET_CREDENTIAL_GUIDE.md) but are not linked from the README.

Task

• Add a "Features" section entry for each with a link to the standalone guide
• Add usage snippet under the CLI examples block
• Add both to the table of contents