* Add CipherListVirtualScroll strategy
For use in cdk-virtual-scroll. Subclasses the default FixedSizeVirtualScroll
but reads the first available itemSize from the rendered content instead of
setting it in the template.
* Fix linting and style
* Refactor virtual scroll strategy
* linting and style
* Subclass virtual scroll strategy directive
* fix linting
* Fix filename conventions
Thomas Rittson