Compatibility with `argparse-manpage`

Refactor construction of argparse.ArgumentParser into a get_argparser() function in each binary.
Set prog property (the default uses sys.arg[0] which breaks with argparse-manpage, arguably this is an argparse-manpage bug).
Set the man_short_description property based on the first line of the description. This is used as a summary in the NAME section of the man page.

cheshirekow / cmake_format