sysutils/ddrescueview: Add new port

Small tool that allows the user to graphically examine ddrescue's
mapfiles in a user friendly GUI application.

Features:
- Display ddrescue mapfile in a colored block graphic
- Examine each block in the image with a detailed list of map
  entries inside
- Zoom inside the mapfile, down to sector level
- To keep track of the rescue process, ddrescueview can automatically
  re-read the mapfile
- Overlay a domain mapfile, if you use one with ddrescue
- Units can be displayed with decimal (KB, MB...) or binary
  (KiB, MiB...) prefixes

WIKI: https://sourceforge.net/p/ddrescueview/wiki/Manual-0.4.5/