Creating Pure-Python Fallback Dependencies

Currently sctk uses pyahocorasick intbitset for license detection & lxml for creating cyclonedx-xml output formats. All three of them are currently implemented as a extension of python using c or cython these libraries are important for the performance of scancode, but they need to be compiled and installed in a specific way, which may not be possible on all computers. This can make scancode less portable or difficult to use for some users who do not have the necessary tools or libraries installed on their machines. Therefore to address this issue the proposal is to create fallback dependencies, that are written in python and can be used by scancode when the required c libraries are not available making it easier to install and use on a wider range of machines