feat: Add C++ backend for strings module

[asmit27rai]

Fixes #670

Brief description of what is fixed or changed

• Added C++ backend for the strings module:
  • Implemented KMP, Rabin-Karp, Boyer-Moore, and Z-function algorithms in C++.
  • Implemented the Trie data structure in C++.
  • Added Python-C++ interface using Python.h.
• Updated _extensions.py in the strings module to define the C++ extensions.
• Integrated the strings module extensions into setup.py.

[asmit27rai]

@czgdp1807 Pls review this PR