Add copy-to-clipboard feature to How To Invoke modal dialog

On the Application UI's "APIs" tab, all of the contracted APIs for the application are listed. Included for each API (if you expand the API in the list) is a "How to Invoke" button, which pops up a modal dialog with information about how to invoke the API.

We should include "Copy to Clipboard" buttons to the API listing table and to the How to Invoke modal.