On newest OS, python2.7 is not installed anymore.

@rafael  or @tomo 

Please feel free to merge in so we can have deployment tests working back again.

/reviewed-on nexedi/slapos.package!101

For most of cases the default approach, with generated certificate, is
enough, but sometimes the playbooks are used in environment, where
real certificates with domain names shall be used.

For such scenarios, prepare the system to use ansible-playbook
--extra-vars which can override the defaults.

Note that frontend requester is improved, to support case of passed or not
certificate files.

As frontend can be already available, but still not serving correct content
check that it returns ZMI (Zope Management Interface) before providing it
as working for the user.

As more then one type of ERP5ish software release can be build
with the playbook, make finding ipv4 more reliable.

Also, as there can be only one public IPv4 drop the playbook_name
namespace from the detected value.

As only two software releases shall be present on a box, assume that one
which is NOT apache frontend is the ERP5 one.

We have no control over how the ERP5 SR will be named, so this change
support this case.

"wendelin" key is used in many places in the playbook and slapos so it
is required to find infromation with this key.

Since "[playbook] Make Wendelin like ERP5" Wendelin became compatible
with ERP5 SR, so compilation detection script shall support it.

By using separated frontend/backend requests and firewall configuration
allow to access ERP5 on public IPv4 of host on https port 443 and http
port 80.

The ipv6 address was not set up before 'slapos format' needed it, so it always failed

Contributed by Kristopher Ruzic (kristopher.ruzic@nexedi.com)