Retire the current tool installation process in favour of a simpler approach

[cat-bro]

The overhead of running GA's tool installation automation has become high relative to the risk of newly installed tools failing.

The github repositories for tools on Galaxy EU and Galaxy Main are much simpler and use yaml files to specify the tool revisions they wish to have installed, then regular ephemeris runs to make sure the state of their toolboxes match what is in the yaml files.

The main problem with GA's process is that it requires human intervention when tools do not pass their tests. In the majority of cases the tool actually is production-ready and has failed a test for a spurious reason. Updates and new installations are often unnecessarily delayed. Now that most tools can run with singularity containers, we can have some confidence that a tool that has got through its planemo checks and ended up in the toolshed will just work.

[cat-bro]

The thing that we would miss most would be the tabular file that shows the date/time of tools being installed and updated.