Contributed by Luke

/reviewed-on !130

Set proper limit.

This is follow-up of nexedi/slapos.core!127

/reviewed-on nexedi/slapos.core!128

This script is tested separatetly

Define smaler Unit Tests files is preferrable to make distribution easier for the test nodes.

This prevents re-declaration to set a diferent default.definition

Introduce this code in order to simplify the code and introduce some kind of reusable API.

Check if the software installation is really well installed before continue

The upgrade_scope is disabled, not never, so added disabled and kept never
for backward compatibility.

Software Installations should be accessible for the users who can also accesss the aggreagted computer

Filter by slap_state makes the alarm don't wait for computer contact (which is unnecessary).

   Drop SlapOSMachineAuthenticationPlugin to use ERP5ExternalAuthenticationPluging instead

   The code was merged into ERP5 Security, so this code is obsolte

This is just a help script to check if Skins are supposed to in the test files

Remove unused code and minor bug fixes