fix UI and model bugs

[gsnider2195]

Closes #222 Closes #233 Closes #245 Closes #275

• Creating Policy Rule Without Name Makes Object Directly Uneditable in UI #233: Fixed name fields being optional on multiple forms.
• Server Error on policy when assigned to dynamic group #222: Fixed server error when navigating to Policy detail view.
• NatPolicy View fails to load #245: Fixed server error when navigating to NATPolicy detail view.
• NatPolicy View fails to load #245: Fixed server error when updating device/dynamic group weights on NATPolicy.
• Capirca breaks with Nautobot v2.3.3 #275: Fixed incompatibility with Nautobot v2.3.3 and higher
• Bonus: Fixed assigned devices and assigned dynamic groups fields not marked as optional on NATPolicy and Policy.

[bryanculver]

What's the behavior change when the assigned items are all blank?

[gsnider2195]

If you're using automatically created form fields then the default behavior is to raise a ValidationError if the form field for this is blank. Since this project is explicitly defining the form fields for these model fields with required=False, this change is effectively a no-op. Based on how the forms were created, adding blank=True is the correct and desired behavior for this model field.