Project title icons

[ghost]

Related Issue: #319

Summary:

• Added an icon that displays the icon for a project's type in the project title display
• Added project title to storybook
• Made the icon grayscale initially, then back to color on hover
• Added a tooltip that says what the project is.
• Refactored the icons in ProjectTypeSelection to be reused.

Screenshots/GIFs:

[AWolf81]

@melanieseltzer no, sorry, I don't remember where it's from. I just know that it was hard to find.

We could take the svg from the Codesandbox example mentioned in my comment in the issue. But a quick fix would be to check the next.js png, if it's possible to set background transparency. It should work because the Gatsby icon is also a png image.

I've noticed from a CI e-mail that a snapshot in ProjectPage.test.js is failing because of this merge. I'll update the snapshot later today. https://circleci.com/gh/joshwcomeau/guppy/749