Remove INSTALL_parallel as the HDF5 build system is now CMake only

[lrknox]

Change reference to INSTALL_parallel to README_HPC.

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Important

Remove INSTALL_parallel and update INSTALL_CMake.txt to reference README_HPC for parallel build information, reflecting exclusive use of CMake.

• Behavior:
  • Remove INSTALL_parallel file as HDF5 now uses CMake exclusively for builds.
  • Update reference in INSTALL_CMake.txt from INSTALL_parallel to README_HPC for parallel build information.
• Documentation:
  • INSTALL_parallel file deleted, which contained outdated parallel installation instructions.
  • INSTALL_CMake.txt now directs users to README_HPC for parallel build details.

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[jhendersonHDF]

There seem to be several bits of parallel-specific information in this file that aren't mentioned in README_HPC such as parallel testing and post-compilation issues. We may want to try to merge some of that information before deleting this file.

[lrknox]

I'll work on adding some of it.

[brtnfld]

Missing:
Test suite troubleshooting
HDF5_PARAPREFIX documentation
Sample programs (or links to)
Detailed configure options

[brtnfld]

Content Migration Checklist

• Build scripts repository reference → README_HPC
• Platform-specific instructions (Linux/Cray) → README_HPC
• Test suite troubleshooting → README_HPC or INSTALL_CMake.txt
• Environment variables (HDF5_PARAPREFIX) → README_HPC
• Sample programs → examples/ directory or README_HPC
• POSIX compliance notes → README_HPC or developer docs

[brtnfld]

See comments

[brtnfld]

Replaced with #5952