Enabled interface monitoring using host vars

[sol1-matt]

Enable interface monitoring on hosts by importing lists of interfaces that can be turned into hosts vars.

There lists available should be

• Up interfaces as strings
• Down interfaces as string
• Optional custom field icinga_vars of type json that changes adds up/down lists that are a list of dicts with the icinga_vars being the dict value

[sol1-matt]

This feature is ready for testing on branch 42-interface-lists.

Of note is the way interfaces are read from the api which is by using giant filter lists, based on the id's of the devices or vm's, that have a arbitrary max length of around 1500 chars.
This has been done to speed up the import from large datasets but could result in problems if a webserver has a max url length lower than this.

[sol1-matt]

expanded the services to create dict of dicts as well as there is similar usage between these

[sol1-matt]

This was added in #45.

It was complicated because we are iterating

• devices
• service
• var values
  to generate useful data

I tried a number of different approaches to generate info and this pull request was the cleanest

It can't handle dict generation for multiple services with the same service name but that is an existing behavior and won't be fixed. Use different service names if it is important.