* table-panel: clickable cell link - draft

* table-panel: clickable cell link - fix link target option

* table-panel: fix undefined columnStyle.link

* table-panel: option to highlight cell with link

* table-panel: render variables for all cells in row

* table-panel: remove cell highlighting

* table-panel: add help for URL field

* linkPopover directive for link info in table panel

* table-panel: add link info popover to cells

* table-panel: use native popover instead directive

* table-panel: link drop refactor, remove unused code

* table-panel: fix unclickable link when drop is opened

* refactoring: minor refactoring to #8738, do not think we need a full blown popover for the links, simple tooltip is enough and more efficient, sadly we do not have a modern tooltip framework, still using old bootstrap 2.3 tooltip

* table-panel: add tests for link rendering