Add "graphicsmagick" tools to Main

[jennaj]

What is does: Convert image formats - pdf option was just added. Plus a montage tool.

quote: "GraphicsMagick is the swiss army knife of image processing."

Why: It will help users to generate publication-quality graphics from Galaxy analysis. This has been asked for many many times. Tools are on usegalaxy.eu already.

PR for PDF addition: bgruening/galaxytools#938

Original enhancement request to IUC: galaxyproject/tools-iuc#2477

MTS repos. We should install both tools from the suite:

Suite: https://toolshed.g2.bx.psu.edu/view/bgruening/graphicsmagick_suite/9154881cc849
Tool1: https://toolshed.g2.bx.psu.edu/view/bgruening/graphicsmagick_image_convert/eb09d7e6d727
Tool2: https://toolshed.g2.bx.psu.edu/view/bgruening/graphicsmagick_image_montage/4dada93ef525

Much thanks to @bernt-matthias for doing the heavy lifting and to @bgruening & IUC team for accepting enhancement idea/final changes :) This will make many many end users very happy!

ping @davebx @martenson @jmchilton Could we roll this into the next tool update? EU keeps these under the "Convert Formats" tool group & think we should put it there, too. Not sure if the "Tool Lifecycle" repo is still used or not, but I am putting it there anyway. It is used for tracking/testing, too, not just requests, ok is not a perfect reflection of what was installed via new auto processes. Assigned dave but is just a placeholder, change or remove that if want. Ping me once installed please so can test it out and get back to a few users who have been very keen on this being added (for pubs).