Put builds into current and previous major columns

[emteknetnz]

Currently rhino builds uses column thats roughtly translate to 'latest major' and 'previous major' columns. However not release CMS 6 compatible branches for many modules, there are now a bunch of modules like bringyourownideas/silverstripe-composer-update-checker, that have broken builds on the 'latest major previous minor' i.e CMS 5.3 which isn't in support

Should make use of supported-modules repository.json to determine where the builds for various things appear so that when you're going down a column, you know it's all the things in say the CMS 6.1 release