upgrade to sc4, fix bundle, more

[brad-decker]

1. Upgrade styled-components to 4 @ beta
2. Refactor extend out
3. Refactor injectGlobal in favor of exporting OPTIONAL global style components
4. Add Rollup that creates two single file bundles
5. Make /pages use our built files instead of src to identify bundle issues sooner.

To do:

• [x] refactor tooltip to use refs correctly
• [x] update docs
• [x] update scripts
• [x] determine best development workflow using rollup + next
• [x] Test in production.

[brad-decker]

1.5K of the diff is in the yarn.lock. most of the files come from changing three lines in all of the icons :(

[merlinbot]

	Messages
:book:	### Modified Components * Avatar * BottomSheet * Chip * Dialog * Drawer * DropdownMenu * FlexGrid * Menu * Portal * Slider * Table * Tabs * TextField * Toolbar * Tooltip ### PR Application * [styled-material-components-pr-325](https://styled-material-components-pr-325.now.sh)

Generated by :no_entry_sign: dangerJS

[brad-decker]

@gregorelee and @danieltisdale done. I made significant changes to the behind-the-scenes stuff with the menu. @gregorelee tag me when you get a minute today and i'll walk you through the expected behavior. @AriLFrankel @ceciliamvrie @martahj might want to tag you on this too make sure i didn't do anything stupid ;)

[ceciliamvrie]

@brad-decker I'm encountering a bug with toggling back the persistent bottom sheet. It works fine when I open it, but it covers 2/3rds of the browser when I try to close it. I don't know if that's introduced in this pr though, but it should be fixed in Merlin Monroe's regressions fix pr (hopefully).

[brad-decker]

@ceciliamvrie thanks! Resolved this one too