Reconsider docs branding

[cliffckerr]

The docs landing page is currently heavily IDM-branded.

• Pro: Shared template with other IDM docsets
• Con: May not advance our goals for this to be an IDM-sponsored, but inclusive and community-led effort. Personally, I would be disinclined to contribute open-source code to an org-branded repo (since I'd assume that their paid staff are taking care of it).

Options:

1. Leave as-is.
2. Keep IDM logo on every page, but make smaller and make the repo name bigger.
3. Keep the IDM logo, but move it to the welcome page rather than branding on every page.

[MObrien-IDM]

I like Option 3 the best.

[JSchripsema-IDM]

The layout of the docs are handled via a template so there are some things that can't easily be updated. We should be able to easily make the logo smaller, but it will always appear on every page as part of the left navigation pane.