Properly include the clipboard library

Problem/Motivation

The module only includes the library in the /shurly route, and not when including the form as a block.

Steps to reproduce

Include the provided block in a site. Check if the JS libraries are loaded for the block form.

Proposed resolution

Move the library attachment to the CreateForm class, and include both JS files into the clipboardjs library definition.

Remaining tasks

User interface changes

API changes

Data model changes