Fixes: #18606 UI Racks Table View Performance Scaling Problem - Loading time increases with large number of racks - django N+1 query issue

[renatoalmeidaoliveira]

Fixes: #18606 UI Racks Table View Performance Scaling Problem - Loading time increases with large number of racks - django N+1 query issue

• The issue happens with the collumns: get_utilization and get_power_utilization
• Both collumns are calculated inside the model
• Adding a prefetch for reservations inside the RackListView queryset partially fixes the problem reduncing the amount of queries from 123 to 85 using NetBox sample data with 42 rack models

Investigating the get_utilization method of the Rack model and comparing with the executed queries in the List view it seens the N+1 queries happens from this line