module.lxc: support for complex network scenariis.

This allow to set additional network nics where the gateway can be setup on.
This allow for exemple eth0 to be on an hostonly network while eth1
is wired to the physical host throught another bridge and eth1 is holding
a publicly addressable IP.

cc @mgw @thatch45 @s0undt3ch @regilero @squizou @jpcw @samaradona
lxc: override default gw
Prep ipv4/6 socket for syndic

Fixes #14736
Sketch of list support for key accept/delete

Refs #14334

@thatch45, tell me what you think of this. Maybe it would be better to
do targets? Not sure.
Update RPM spec for 2014.1.10
provide support for VPC security groups in boto_secgroup state module
Deploy /var/cache/salt with common RPM

Also changed the deprecated $RPM_BUILD_ROOT to %{buildroot}.
Disable service.py for entire SUSE family >= 12

Checking os_family allows us to pick up openSUSE and SUSE Linux Enterprise, rather than just checking for os == openSUSE.
Removed 0.17 requirement note from formula docs

0.17 is no longer a supported release.
Moved the Formula Conventions CHANGELOG section down next to Versioning

This section is less important for new users than the mapfile and sls
recommendation sections.
Improve and shorten the Formula lookup table recommendation
Updated the Formula README recommendation
Added link targets to a few requisite types
Improved the simple Formula usage example at the top
Improved the Formula installation docs with examples
Improve and clarify the Formula docs on using formulas from non-formulas
Moved the Formula repository structure docs to the bottom

We should describe best practices for writing formulas first.
Fleshed out the recommendations for writing reusable formulas
Removed the redundant platform agnostic Formula section
Fleshed out Formula Parameterization section