stansummary utility: swap out use for boost::program_options package for cli11

[mitzimorris]

Summary:

Use header-only lib cli11 instead of boost::program_options to parse command-line args
for stansummary utility.

Description:

Use of boost::program_options to parse command line was introduced by #890. Since this is a non-header only lib, and requires bmake, it required quite a bit of makefile hacks - now the
makefiles are more complicated and we're seeing new problems - cf #928

Reproducible Steps:

see #928

Additional Information:

https://iscinumpy.gitlab.io/post/comparing-cli11-and-boostpo/

Current Version:

v2.24.0