Deprecating $FAST / --fast

As this option shows inconsistencies / wrong results and a fix would require
too much work at this moment this option is being hidden from the help. It
wasn't in the ~/doc .

See #849 , #2382, #1732 etc.

testssl.sh

@@ -20343,7 +20343,6 @@ single check as <options>  ("$PROG_NAME URI" does everything except -E and -g):
      -4, --rc4, --appelbaum        which RC4 ciphers are being offered?
 
 tuning / connect options (most also can be preset via environment variables):
-     --fast                        omits some checks: using openssl for all ciphers (-e), show only first preferred cipher.
      -9, --full                    includes tests for implementation bugs and cipher per protocol (could disappear)
      --bugs                        enables the "-bugs" option of s_client, needed e.g. for some buggy F5s
      --assume-http                 if protocol check fails it assumes HTTP protocol and enforces HTTP checks