This PR is for part 1 of #1354. It focuses on adding a model selection
interface for models that exist in `photonvision_config/models/`. Upon
completion we can ship more than 1 model and users could upload their
own through `ssh` without deleting the shipped model. This PR also adds
the abstractions need to support more DNN backends (say OpenCV, or RPI
AI Kit)
Up next is adding a CRUD interface for managing models through the UI.
Tested on Orange Pi 5 and Cool Pi 4B. Merge with parts of the OpenCV DNN PR.
Adds support for YOLOv5s models for Rockchip CPUs with a NPU. Right now hard coded to a note model from alex_idk. Very much still incubating and largely untested.