Bedholder support

These are supports to prevent the bedholder from @AngryPearl (https://makerworld.com/en/models/690688) from sliding when removing or placing a bed plate into the bed holder. No tape or anything needed. Both parts are simply placed under the X1C at the feet which prevents all movement. NOTE: I have the antivibration feet installed. It has not been tested with the regular X1C feet. It might to high for the regular feet.