refactoring: extract custom element from html template

[atsu85]

Would be nice, if it was possible to select chunk of html from existing Aurelia html template and after entering path and basename of the extracted custom element, it should create new custom elemenet (html and TypeScript) files.

There is a menu item, that seems to be meant just for that (maybe it works for JSP or other technologies?): Refactor -> Extract -> Extract include file