Form states: set form-control state based on form-group and handle sm and lg size

Created by: pvdlg

Per documentation:

To use, add .has-warning, .has-danger, or .has-success to the parent element. Any .col-form-label, .form-control, or custom form element will receive the validation styles.

Contrary to what's mentioned in the documentation the classes form-control-success, form-control-warning and form-control-danger are currently required on the form-control.

This PR conforms the code with the documentation and apply the state styles on the form-control based on the state class set on the parent form-group. The behavior of form-control is now similar to form-control-label (takes it's state styles from form-group).

In addition this PR set the position of the state icon based on the form-control size. So if form-control-sm is used with has-success the icon is now sized and positioned properly.