science/gramps: Update to 4.2.3

• Take maintainership
• Convert to USE_GITHUB (new location of main upstream repository)
• Update dependencies for new version (namely python 3.2+ and GTK3) [1]
• Convert "strongly recommended" options to dependencies (removing option) [1]
• Add "optional" dependencies as OPTIONS [1]
• Remove pkg-plist and convert build to USE_PYTHON=autoplist distutils
• Remove pre-extract upgrade warning as it is ineffective for pkg upgrades and now only applies for systems which have not been upgraded in 1.5 years.
• Add post-stage hack to fix staging support, copied from Arch Linux [2]
• Delete files/patch-src_gramps.py as the offending file has been removed
• Add files/patch-setup.py to allow "--single-version-externally-managed" [3]
• Add files/patch-setup.py to fix double slashes in generated by autoplist [4]
  
  Changes:
  
  https://github.com/gramps-project/gramps/blob/v4.2.3/NEWS
  
  [1] https://github.com/gramps-project/gramps/blob/v4.2.3/README [2] https://projects.archlinux.org/svntogit/community.git/tree/trunk/PKGBUILD?h=packages/gramps&id=ee1c7fae15872481d8f55868f4211efcbce15314 [3] https://github.com/gramps-project/gramps/commit/ab67c786b03552ce4b0ac8f0ed9d7af228d46fe4 [4] https://github.com/gramps-project/gramps/pull/96

PR: 207005
Reviewed by: mat (mentor)
Approved by: adamw (mentor)
Differential Revision: https://reviews.freebsd.org/D6439