v3.6 database migration logic is inefficient for large numbers of device types #13745
Description
NetBox version
v3.6.1
Python version
3.8
Steps to Reproduce
This is an extension to bug #13605, which was addressed for device and virtual machines during the v3.6 beta testing period. The issue described therein impacts device types as well, as raised in discussion #13676.
Expected Behavior
Schema migrations should apply without error, and should not consume excessive disk space or memory.
Observed Behavior
Attempting to upgrade to v3.6.0 or later with a large number of device types (over 3,000 as tested) can trigger excessive disk space utilization due to inefficiencies in the component template count logic.
We should be able to resolve this in a manner similar to the fix for #13605.