Add system location to configuration file

[ByteOtter]

What does this PR change?

As the Netbox API requires a location for the system that is to be registered, we need to be able to hand netbox-sync this property. With this PR the user can either enter this property via a -l / --language flag or specify it in the config file.

An example of this config file would be:

[netbox]
netbox_api_token = "netbox.company.de"
netbox_uri = "drrth429rthj894ghhkdjfhwlgz48g3hjhvjgerg34"

[system]
system_location = "Berlin"

Tick the applicable box:

• [x] Add new feature

• [ ] Security changes

• [ ] Tests

• [ ] Documentation changed
  

• [ ] General Maintenance

Links

Fixes: #31

• [x] DONE

Documentation

• No documentation needed
  

• [x] DONE