feat: Added Theme and migrate to emotion@10.x 🚀 (#286)

* chore: updated emotion dependency

* feat: introduced theme

* refactor: updated emotion styles

* fix: fixed emotion error

* fix: fixed tests

* chore: add missing types

Co-Authored-By: Thomas Klein <tmkn@users.noreply.github.com>

src/design-tokens/ThemeProvider.tsx

@@ -0,0 +1,13 @@
+import React from 'react';
+import { ThemeProvider as MuiThemeProvider } from '@material-ui/core/styles';
+import { ThemeProvider as EmotionThemeProvider } from 'emotion-theming';
+
+import theme from './theme';
+
+const ThemeProvider: React.FC = ({ children }) => (
+  <EmotionThemeProvider theme={theme}>
+    <MuiThemeProvider theme={theme}>{children}</MuiThemeProvider>
+  </EmotionThemeProvider>
+);
+
+export default ThemeProvider;