x11-wm/libdockapp: Update to 0.7.2

While I'm here:

• Change MASTER_SITES to upstream's new location
• Add license and path to the license file
• Sort variables a bit according to the PHB
• Simplify pkg-plist substitution for the installation of example files

Add some patches as well as just bumping the port revision for the following
ports due changed location of the header files:

• net/wmnetload
• x11/xscreensaver.app

Changelog:

https://github.com/d-torrance/dockapps/blob/master/libdockapp/ChangeLog

PR: 235923
Approved by: miwi (mentor), maintainer timeout
Differential Revision: https://reviews.freebsd.org/D19508