CameraITS: create Chart class to store chart, size, distance, etc.

Allows flexibility for future added scenes with different charts.
Also define chart.locate() and chart._calc_scale_factors().
chart.locate() now takes the format argument to allow locate
method to find chart with same format as rest of test.

Change-Id: Id1d4f9585f95356ba55fa5c1e842608bfe2552d6
3 files changed