Major rework and update of SDK bindings

[daniel-j]

Features

• Nimble integration. Use nimble tasks to configure, build. piconim has gained some features as well, and can be used for more advanced building
• Pico W support. Wifi and Bluetooth bindings using Futhark
• Updated and added new bindings to support Pico SDK v1.5.1, striving to be pretty much 1:1, with some Nim goodness added here and there (shorter method names, distinct types, ranges, enums...)
• More examples, translated from C to Nim from the pico-examples repository
• More robust CMake-based configure and build process to work as smoothly as possible with Nim
• Code examples and the SDK bindings are compiled when running nimble test and nimble examples.
• Proof-of-concept hand-crafted Cyw43 and (partial) Lwip bindings, which I made before adding Futhark. Enough to do HTTPS requests on the Pico W.
• Change license to match Pico SDK's (BSD-3-Clause)
• Can choose board type when running piconim init --board pico_w projectName

Future improvements

• Tinyusb. I haven't touched it at all, so probably needs work
• Update all examples to the new codebase
• Test the examples on real hardware and make sure they work
• Generate html documentation and host it somewhere. Some doc-comments needs updating to RST first
• Github workflows for running the tests on the different platforms
• Bluetooth tests and examples
• FreeRTOS support when using Wifi. Would be nice to use the Nim stdlib to do http requests