Simplify the Switch implementation

Currently, the switch component requires a bit of complex structure with a nested label and such. There are ways to simplify it to just use a single checkbox and label like a normal control.

Note: We will want to also update the https://github.com/RoleModel/rolemodel_rails/blob/master/lib/generators/rolemodel/simple_form/templates/app/inputs/switch_checkbox_input.rb that goes along with this.