Plugin Administration: blocktype page needs to be made accessible

[Lisa Seeto]

The page "Plugin Administration: blocktype" (admin/extensions/plugintypeconfig.php?plugintype=blocktype) needs to be made accessible for keyboard navigation, and for screen readers.

Currently the page relies on a drag and drop option via the mouse to re-order the blocks to prioritise the display order when they appear in the configure block modal of the placeholder block.

Currently there is no way to achieve the block re-ordering without mouse usage. Is it possible to create a solution where a keyboard user can select to "highlight" a block and then navigate to a new area, "place" the block and have the block now appear there?

This may be a useful article about keyboard driven drag and drop functionality that could provide some insight into solving this issue: https://medium.com/salesforce-ux/4-major-patterns-for-accessible-drag-and-drop-1d43f64ebf09

Some things to keep in mind for screen readers:
- The block title needs to be clearly labelled as well as the number of times it appears, i.e, "Image block, used 3 times" also if there are any changes to the way this page labels the order of the blocks, i.e "Image block, used 3 times, position 1" than that will also need to be perceived by a screen reader.