IPAM Overhaul: Refactor utilization/allocation calculation logic

[lampwins]

• Based on IPAM Overhaul: Prefix-Prefix Parent Concrete Relationship #2915, make calculations work
• Separate UI context for prefix vs IP address calculations
• Address subnet "over" allocation #2648

[bryanculver]

Need to do #2531 so solving this with that story (and IPAddress) while moving the existing code.

[gsnider2195]

Action items from design meeting:

• Prefix type network can only contain IP addresses and prefix pools
• Prefix type container can only contain child prefixes
• Prefix type is user serviceable and defaults to Container
• Bring back the is_pool property
• IP Address parent property cannot be set to a prefix with type pool, it will parent to the nearest network prefix
• Prefix utilization should be split out into two columns, where calculations are based on the prefix type
  • Container shows utilization as sum of the size of direct child prefixes
  • Network shows utilization as sum of the number of direct child IPs and the size of any child pools
    • ⭐ Direct children of networks that are members of a pool are going to be counted twice
• IPAddress and pool views should show ipaddress/pool relationships through net_contains lookups
• Pools cannot contain child prefixes or ip addresses

This is going to require us to revisit the IPAM data migrations for prefix/ip address parenting

[gsnider2195]

Adding a second utilization column slows down the list view even more (over 5 seconds to load 46 prefixes on my dev machine). I'm going to combine the columns for now.

[glennmatthews]

Fixed by #3873.