Revert "Framelayout for recyclerview and appbar"

This reverts commit 91b41804.

Reason for revert:

This CL breaks a lot of user journeys on DocsUI unfortunately. If you try DocsUI in landscape, particularly on a work profile device where you get personal/work tabs, there is no area left to see and scroll your files.

If you increase the font size or dispaly size (important accessibility features), or have a smaller display (important as this is the default file picker on all GMS devices), it will be even less usable and I'm pretty sure will have no area left to see and scroll your files at all, even without a work profile.

Change-Id: I23609293e7428b130e4d2141856d7a316437f617
Bug: 141108476
Fixes: 152614453