Charmed Install Updates from v7.0

Removal of iptables manipulation from charmed installer
Expose juju controller using metallb
Pin version of juju

Change-Id: I3853dfe1d3b264311bed1f3a805397a9197b10bc
Signed-off-by: beierlm <mark.beierl@canonical.com>
(cherry picked from commit 3749e310)