Fix isInternalUrl for subdomain support

Refactor / reduce plumbing

app/components/HelpText.js

@@ -0,0 +1,10 @@
+// @flow
+import styled from 'styled-components';
+
+const HelpText = styled.p`
+  margin-top: 0;
+  color: ${props => props.theme.slateDark};
+  font-size: ${props => (props.small ? '13px' : 'auto')};
+`;
+
+export default HelpText;