user, group, & permissions fix

Use black as formatter for python files

Fix custom fields initializer

Fixed creation of passwords for Netbox 2.9

Permission handling in external function ...

This move the setting of user and group permissions in the startup
script to its own function.

Add function to load YAML files ...

This commit starts to remove some code redundancy from the startup
scripts for easier maintenance.

Tiny code refactoring

Removed the eval from the code ...

... and changed it to make it work with the latest Netbox version.

simplify yml definitions to use wildcard syntax

adjust groups and users startup scripts to allow custom codename filter

adjusts users and groups startup scripts to accomdate non-uniqueness

Ignore missing initializers ...

Previously, the startup_scripts would fail if an initializer file was
not present. Now they just ignore missing files.

Increase order prefix to 3 digits