Add Harris enrollment visual

What does this PR do?

[x] The title of the html page is the same as the chart.
[x] The meta_data.json file is filled in correctly (the description is a complete sentence, the title is the same as the visual).
[x] The chart and its associated pages have been minified using the npm run process-visual command.
[x] The visual is styled similar to other charts (centered title/subtitle, no legends unless absolutely necessary, etc.)
[x] This visual was approved by the lead developer.
[x] The visual was approved by the story's stakeholders.