[llvm] [nfc][llvm-profdata]Refactor llvm-profdata show* code, by moving function-scope options to a show_llvmprofdata namespace (PR #71328)

[David Li via llvm-commits]

https://github.com/david-xl commented:

Better put the options into its own name space "namespace show_options {}. In the follow up patch, options for other commands can be done similarly. 

https://github.com/llvm/llvm-project/pull/71328