Support null terminated string types

[emesare]

https://docs.python.org/3/library/ctypes.html#ctypes.c_char_p https://docs.python.org/3/library/ctypes.html#ctypes.c_wchar_p

memflow already supports reading null terminated strings. Only on UTF-8 encoded strings, however. We will need our own for c_wchar_p.

[emesare]

Preliminary support added with: https://github.com/memflow/memflow-py/commit/e76e46e050a9d333227897dd7add41513da98b92. Once we move to deduplicate our memory read/write functions, broad support for these null terminated string readers will be added.