Add Prettier for linting and fix Solhint config (#2697)

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

contracts/utils/Arrays.sol

@@ -8,7 +8,7 @@ import "./math/Math.sol";
  * @dev Collection of functions related to array types.
  */
 library Arrays {
-   /**
+    /**
      * @dev Searches a sorted `array` and returns the first index that contains
      * a value greater or equal to `element`. If no such index exists (i.e. all
      * values in the array are strictly less than `element`), the array length is