Change SVG injection method

I know we don't have a good consensus on how to handle docs > svgs. This isn't to tackle that.

@augurone had the great suggestion that we should be injecting the SVGs instead of using an image tag. This is definitely better for colorizing and animating... likely more things.

No files or tests are named. Start by locating how the website currently renders SVGs and where image tags are used; confirm the existing behavior before choosing the injection point. Done means the relevant SVGs are injected rather than referenced through image tags, with the proposed support for colorizing and animating preserved.

Written by the indexing model from the issue text.