Make the UI more flexible

Problem/Motivation

We are currently using 'tableselect' to display configurations items. This is good to display only a checkbox with a few options, but fails to extend the UI in the future.

Also, we have the same code three times for 'Tracking', 'Not Tracking' and 'Migrate -> Export' lists. Is hard to mantain and hard to extend.

Proposed resolution

Modify the UI to reuse parts of the code, use a theme function to render the table instead of a tableselect form item.

User interface changes

None

API changes

None