Update minimum Clang version requirement to Clang 18

[loudsun1997]

Fixes #175.

Summary
• Updated minimum Clang version to Clang 18.
• Clang18 builds successfully but requires CUDA 12.8 on NVIDIA systems. CUDA 12.4 is not supported with Clang 18.

Notes
• Tested on WPI Turing, Tuo and Tioga systems.
• Users must upgrade to CUDA 12.8 or later for NVIDIA systems.

This pull request includes several changes to update the project to require Clang 18.0.
The most important changes include updating the CMake configuration, removing conditional compilation based on older Clang versions, and cleaning up the codebase.

[tpatki]

• @loudsun1997 : Please run the check-c-code-format.sh in the scripts directory to format the code.
• @tpatki and @slabasan need to update GitHub CI checks to Clang18 only.
• @tpatki Need to test on Tioga/Tuo.

[tpatki]

Things we need to fix:

• Remove the hostconfigs that are clang 10-17
• Create a new hostfile for Tioga for amdclang-18
• Create a new hostfile for Tuo for amdclang-18
• Clean up comments with older clang versions (weave_common, weaver-CMakefile), check other places for things that are commented and mention Clang9-17.
• Clean up LLVM pass messages other than NewWeavePass loaded successfully! (appear when building smoketests)
• Remove PERFFLOWASPECT_CLANG_18_NEWER from build