This copy button manages a local instance of the Clipboard plugin
specific to it, which means it is created/destroyed on the
creation/destruction of the component. This allows it to work well in
gitlab-ui modals, as the event listeners are bound on creation of the
button.
It also allows for bindings to the `container` option of the Clipboard
plugin, which allows it to work within the focus trap set by bootstrap's
modals.
