cxxscript: new recipe for 0.1.6

[sujithsuranga]

Summary

Adds a new recipe for CxxScript, a modern, embeddable C++ scripting engine for running .script procedures from a host application.

• Homepage: https://slightlabs.github.io/CxxScript/
• License: MIT
• Package type: library (static library via CMake)

Notes

• CXXSCRIPT_BUILD_TESTS / CXXSCRIPT_BUILD_EXAMPLES are disabled in generate() so GoogleTest is never fetched over the network and demo binaries are not built.
• The upstream build exports its own CMake package config files under lib/cmake/CxxScript; these are removed from the package in package() since Conan's CMakeDeps generates the ones consumers use, and cpp_info sets cmake_file_name/cmake_target_name accordingly.
• Verified locally with conan create . --version 0.1.6 --build=missing (test_package builds, links, and runs successfully).

Checklist

• I've read the contributing guidelines.
• I've used a name and version already used or an exception has been previously approved.
• I've read the How to add packages guide.
• I've followed the PR guidelines.

[CLAassistant]

All committers have signed the CLA.