Netbox 4 compatibility

[matejv]

List of items from official plugin porting guide:

General
    ✅ Python support
    ✅ Plugin resources relocated
    ☑️ ContentType renamed to ObjectType (I think I fixed those that need to be fixed)
Views
    🟡 View actions must be dictionaries (not in use) 
Forms
    ✅ Remove BootstrapMixin
    ✅ Update Fieldset definitions
Navigation
    ✅ Remove button colors
UI Layout
    ✅ Renamed template blocks
    🟡 Utilize flex controls (not in use)
    🟡 Check column offsets (not in use)
    ✅ Tables inside cards
    ✅ Remove btn-sm class from buttons
    ✅ Update bg-$color classes
    🟡 Obsolete custom CSS classes (not in use)
REST API
    ✅ Extend serializer for brief mode
    ✅ Include description fields in brief mode
GraphQL
    Change schema.py
    Change types.py
    Change filters.py

Other stuff:

✅ count_related moved
asset_edit template - check
check all other complex templates
✅ The annotated_date template filter and annotated_now template tag have been removed.
✅ move all nested table action buttons from footer to header
✅ change how htmx tables are rendered (new macro) 
on custom tabs for core objects (tabs folder), fix controls button layout
✅ update warranty progress bar component
update render_table to htmx
investigate image attachments includes if it's possible to hide object type & parent columns

[matejv]

Test should pass and basic functionality should work.

Still need to check and update a bunch of templates and other minor stuff...

[matejv]

A few issues I identified and not yet fixed are ether netbox bugs, bugs from existing version of the plugin (and are not straightforward to fix) or other small issues that can wait a bit.