container: T6701: add support to disable container network DNS support (#4052)

Add ability to set the container network with a disable-dns setting to disable
the DNS plugin that is on be default.

  set container network <network> no-name-server

(cherry picked from commit 1d5625d572cc25a9d53247b7c41177f17845b052)

Co-authored-by: Dave Vogel <dave.vogel@fullpower.com>