Reusable element for drag and drop sortable table or list

This is a proposal to implement a re-usable template and JS module to allow moving table rows or list elements.
Each UI should be able to use it by specifying an AJAX callback on completion.
It should be possible to set the first row/element as non-draggable, maybe there are use cases for more than one row/element.

Use cases:

• rearranging sections - exists but non standard
• rearranging activities - this may be a bit trickier because they can be moved to other sections, i.e. outside of the initial ul element
• changing courses sortorder in the course and category management interface - exists but not standard
• changing categories sortorder in the course and category management interface - MDL-42297
• changing courses order in "course overview" block - exists but not standard
• changing order of enrolment methods - MDL-29302
• filter plugins list, course format plugins list, question types, repositories, etc.
• any table in Moodle where we have arrows up and down to sort