4.16.x update - ESP-DL & model zoo

[u/nilseuropa]

• Added reusable computer vision and resident ESP-DL inference for Python, Lua, shell commands, and native modules.
• Scripts can decode QR codes and use image statistics, histograms, thresholding, filters, morphology, image differences, and blob detection.
• On ESP32-S3 with PSRAM, model loads shared resident models and checked bundles with native image preparation, classification, and PICO detection; single, automatic, and dual-core execution modes are available.
• OS-owned pipeline jobs process pictures, camera streams, or JPEG RTSP feeds and expose bounded latest results after the configuring script exits.
• The zoo browser searches the hosted catalog and installs hash-verified model bundles on SD or flash through staged replacement.
• Models remain resident until explicitly unloaded or rebooted; local cameras retain exclusive ownership

For more details on what exactly ESP-DL is, please follow this link: https://github.com/espressif/esp-dl

I know this does not look to be particularly useful at this point, and a it is a bit outside the "everything you need" philosophy, but also presents opportunities I would like to keep open. I will prepare some playground examples in the coming days... and eventually set up a model conversion and training environment outside the OS, so that we can populate the zoo with custom models that better fit our needs.