science/cdf: improve and lint port

• Lint and sort Makefile according to portclippy(1)
• Mark as PIE_UNSAFE
• Split post-install stance to respect DOCS and EXAMPLES options
• Strip installed binaries and libs
• Use dynamic SOVERSION via PLIST_SUB

Approved by: yuri@ (Mentor)

Differential Revision: https://reviews.freebsd.org/D52408