Pylibtiff

* Remove deprecated `setuptools_scm_git_archive` package from build process
* Remove unused matplotlib and wx imports in CLI scripts

* Add libtiff 4.6.0 wrappers
* Remove GUI functionality from scripts

* Fix "scripts" sub-package
* Various ctypes fixes
* Add TIFF_HEADER_PATH to force header location
* Fix handling of line continuations with libtiff 4.5.0

* Add missing README.md from source distribution (used to as long_description in package metadata)

* Major package structure and CI overhaul
* `libtiff.info` and `libtiff.convert` scripts are now setuptools entry points (console_scripts). Functionally the same, but code is executed differently.
* Remove unused bundled bitarray
* Fix numpy `np.bool` usage

Various updates and bug fixes.