Switch performance testing to use local files

[arschmitz]

To avoid network overhead skewing test results we should look at using local files rather then cdn links.

[sfrisk]

This was discussed in today's meeting. Along with local files to prevent network from skewing tests, it was also suggested that we look at appending as well as scrolling for performance testing as a meaningful way to measure the rendering performance of a particular component's markup and css.

Specifically 3 different types of tests: Appending, Scrolling, Appending + scrolling.

Naturally, some of the priorities of performance testing shall change when we start using it for CI on Chassis.