Addition of pickle and lief, extension of corpus, and others

• The training corpus can be pickled, for faster startup time.
• Lief can be used as an alternative for elfesteem
• GitHub action to automatically test portability to multiple environments (OS and python variants)
• CodeQL warnings are resolved.
• Some new architectures since last release (XtensaEB, ARC32eb, ARC32el, WebAssembly, CUDA, TriCore and 78k howto, Trimedia, H8S, 6502).
• Display Shannon entropy when running with binwalk.
• And some documentation.