UI fixes

Summary:
This is a collection of small UI fixes for the network plugin:

- image maxWidth is set to 100% to not cause vertical scrolling
- Panels now have horizontal scrollbars, if their content overflows
- fixing missing icon for failed network requests
- removing position sticky from table headers as it was not used and causing some rendering issues and performance problems
- Adding a `label` and `grow` option to the `Select`-component which is used in the sidebar of the network plugin.

Reviewed By: passy

Differential Revision: D12956336

fbshipit-source-id: 6e7e9cf97c058a2ff626576d4afdc6df65007ea1

src/ui/components/table/TableHead.js

@@ -49,7 +49,6 @@ const TableHeadContainer = styled(FlexRow)({
   flexShrink: 0,
   left: 0,
   overflow: 'hidden',
-  position: 'sticky',
   right: 0,
   textAlign: 'left',
   top: 0,