Refactor code to use abstract classes and PIMPL #141

Job	Run time
pre_job	7s
libraries	5s
changes	3s
lint / clang-format	11s
lint / cppcheck	18s
docs	0s
macos / examples	34s
windows / examples	2m 8s
windows / tests	2m 1s
macos / tests	34s
python / tests	49s
linux / examples	53s
linux / tests	48s
macos / rust (macos-14, arm64)	34s
macos / rust (macos-14, x86_64)	53s
macos / build (static, arm64)	30s
macos / build (static, x86_64)	33s
macos / python / build-wheels	5m 8s
python / sdist	19s
linux / rust (ubuntu-20.04)	1m 2s
linux / rust (ubuntu-22.04)	1m 3s
linux / build (dockcross/linux-x64, linux-x64, simpleble, static)	1m 21s
linux / build (dockcross/linux-x86, linux-x86, simpleble, static)	1m 38s
linux / build (dockcross/linux-armv6-lts, linux-armv6, simpleble, static)	1m 22s
linux / python / build-wheels	20m 50s
windows / build (Win32, static)	2m 14s
windows / build (x64, static)	1m 58s
windows / python / build-wheels	8m 0s
release-python	0s
	55m 56s

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