Add typings for reactstrap (#15357)

* Add typings for reactstrap

* Make lint happy

* Do not „double-reference“ to React types

reactstrap/lib/Button.d.ts

@@ -0,0 +1,16 @@
+interface Props extends React.HTMLProps<HTMLButtonElement> {
+  outline?: boolean;
+  active?: boolean;
+  block?: boolean;
+  color?: string;
+  disabled?: boolean;
+  tag?: React.ReactType;
+
+  onClick?: React.MouseEventHandler<any>;
+  size?: any;
+  id?: string;
+  style?: React.CSSProperties;
+}
+
+declare var Button: React.StatelessComponent<Props>;
+export default Button;