devel/apr1: Update to 1.6 branch

• Update APR to 1.6.0
• Update APR-util to 1.6.2
• Add UPDATING entry
• Ungroup APR
• Add missing descriptions
• Switch to using OPT_VARS
• Add ODBC driver
• Remove FreeTDS driver and patch
• Remove Windows files from WRKDIR not WRKSRC
• Cosmetic fixes
• Update patches for new version

Reviewed by: ohauer (maintainer)
Approved by: ohauer (maintainer)
Differential Revision: https://reviews.freebsd.org/D11285