Clean up: Get rid of licenseOptions code

[timbl]

The licenseOptions code was a UROP project back in the Tabulator project days which allowed a user to select a set of data licences (like Creative Commons, etc) which they wanted for their data, and then automatically have data in that set of licences be displayed with a suitable highlight (pale green background).

(One could imagine making the feature in the future also keep track of what sort of use the user is putting the data, and then checking that appropriate consent has been given for them.)

This feature has not been used for many years, and has no tests, and so I propose to remove it.