[SPIKE] Scope changes needed to fix image content for dark theme

As a developer, I want to be able to come up with a strategy on how to handle images in the console with regard to displaying them in dark theme.

In the code there are svg's and png's, and there needs to be a unified strategy between uxd/admin/dev console on how to move forward with images and dark them. 

If we can convert all svg's to xml svg's, after that no additional work needs to be done for that image type since it uses a background color variable. Win!

For other images we need to figure out how to move forward. ie do we reference two images per callout: one for dark theme, and one for light theme? how do we make contributors aware of this change?

Acceptance criteria:

1. Investigate an automated way to convert svg to xml svg
2. Come up with a strategy for png content. Involve uxd for this item.
3. How do we handle catalog view?
4. Produce follow on story/stories to implement the strategy defined in this spike.