Motivation for this change

Add ImageJ (an image processing/analysis software).

Things done

• Tested using sandboxing
  (nix.useSandbox on NixOS,
  or option build-use-sandbox in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • Linux
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.
• meta.maintainers is set (by adding an email address to default.nix; no entries were added to lib/maintainers.nix)

Possible improvements

• According to the official documentation, should be able to compile and run
  ImageJ by using JDK version 48 ("JDK 1.4") or later.
• The binary version (packaged here) provided by NIH appears to be compiled
  using the JDK version 49 ("JDK 5"), and thus should work on every platform
  where a JRE of version 49 or later is available.