Dashboard App: Rename it to Launch Pad

[zcolah]

Problem Since we manage websites and its common to have a "home" or "homepage". It is really confusing to therefore have a home tab and a homepage content item and a homepage model. Customers often click it expecting to edit their homepage.

Solution To avoid confusion, we will rename Home to Launchpad. Please see Design Spec for the same: https://www.figma.com/file/7ro1VVY7ClS4mG3Wiom3Hs/Dashboard-App?node-id=677%3A34411&t=yYcx9cyT9o0VxElg-1