Some fixes in rendering legacy plugins

Summary:
Some exploratory testing on all iOS and Android plugins, to see how they behave inside Sandy, and fixed some layout glitches (some were also present without Sandy)

General fixes:
* Introduced some niceties like searchbox resizing properly, and toolbars wrapping automatically in Sandy, rather than buttons becoming invisible
* Containers don't grow anymore by default, but take size of contents
* ScrollContainer child is now a Layout.Vertical. Layout.Vertical should be used as default container everywhere (e.g. Tabs, Panels) in the future
* Fixed layout issue if a split container had only 1 visible child
* DetailsSidebar now scrolls vertically by default
* Details sidebar would sometimes render content in-place rather than in the reserved area
* AppSelector dropdown and Plugin list will now properly ellipse (...) if there is not enough space

Plugin fixes:
* Long database / table names in Database plugin would break layout

Also fixes https://github.com/facebook/flipper/issues/1611

Reviewed By: passy

Differential Revision: D24454188

fbshipit-source-id: c60c867270900a1d4f28587d47067c6ec1072ede

desktop/app/src/PluginContainer.tsx

@@ -49,6 +49,7 @@ import {ToggleButton, SmallText, Layout} from './ui';
 import {SandyPluginRenderer} from 'flipper-plugin';
 import {isDevicePluginDefinition} from './utils/pluginUtils';
 import ArchivedDevice from './devices/ArchivedDevice';
+import {ContentContainer} from './sandy-chrome/ContentContainer';
 
 const Container = styled(FlexColumn)({
   width: 0,
@@ -436,7 +437,7 @@ class PluginContainer extends PureComponent<Props, State> {
           heading={`Plugin "${
             activePlugin.title || 'Unknown'
           }" encountered an error during render`}>
-          {pluginElement}
+          <ContentContainer>{pluginElement}</ContentContainer>
         </ErrorBoundary>
         <SidebarContainer id="detailsSidebar" />
       </Layout.Right>