Briefly document all programs in manpage
Fix Makefile

* Prefix each command with atk6-.
* Install manpage as attack-toolkit6.
* Add LDFLAGS when building dnsdict6 to include hardening stuff.
  Fixes lintian warnings:
    - hardening-no-fortify-functions usr/bin/dnsdict6
    - hardening-no-relro usr/bin/dnsdict6
* Remove script extension as per policy 10.4.
* Install to /usr.