[FEATURE REQUEST]: Popover missing component option as html template

Feature description:

As there are existing options for popover template like uib-popover, uib-popover-html and uib-popover-template, there could be one more for component, e.g: uib-popover-component. At the moment I was able to resolve in some way only by passing separate template, where component is rendered.

Link to minimally-working plunker that reproduces the issue:

http://plnkr.co/edit/F3KPDwYv9XnAyOgOZtfP?p=preview

Version of Angular, UIBS, and Bootstrap

Angular: 1.6.4

UIBS: 2.5.0

Bootstrap: 3.3.1