Theming colors

Summary:
This diff adds Sandy colors and dark mode support to the `DataInspector` and `LayoutInspector` components, and coverts hardcoded colors to semantic colors. Currently only one set of colors is used since they contrast fine with both dark and light mode, but this could be deviated from now onwards.

Also styled the legacy ManagedTable and Panel, since they are so commonly used (will convert more legacy components in next diffs).

Reviewed By: passy

Differential Revision: D28056698

fbshipit-source-id: 5a85103983f89e82b7f000d309bb9e1e1f07491d

desktop/plugins/public/layout/InspectorSidebar.tsx

@@ -9,7 +9,6 @@
 
 import {
   ManagedDataInspector,
-  Panel,
   FlexCenter,
   styled,
   colors,
@@ -18,6 +17,7 @@ import {
   Client,
   Logger,
 } from 'flipper';
+import {Panel} from 'flipper-plugin';
 import {PureComponent} from 'react';
 import React from 'react';
 import {useMemo, useEffect} from 'react';
@@ -64,7 +64,7 @@ class InspectorSidebarSection extends PureComponent<InspectorSidebarSectionProps
   render() {
     const {id} = this.props;
     return (
-      <Panel heading={id} floating={false} grow={false}>
+      <Panel title={id} pad>
         <ManagedDataInspector
           data={this.props.data}
           setValue={this.props.onValueChanged ? this.setValue : undefined}