ISIS-537 Use btn-warning for the prototype application actions

https://trello.com/c/mouPyHEL/57-styling-of-disabled-and-prototype-actions-nb-for-buttons-as-well-as-menu-items
ISIS-537 Reduce the width of the Select2 input to make it show its left border again

https://trello.com/c/o0vFAKrc/93-select2-misses-left-border-in-modal-windows