Add copyright page as a frontmatter type
Context
A copyright page is often standard in (even open) books. The PagedJS templates need to account for copyright page styling as well. Currently there are a few frontmatter types but copyright page would be a useful addition because of how commonly it's needed. Plus there are really exciting ways copyright pages could be made use of in future (for example automatically pulling book metadata into the copyright page to avoid dual master problems).
Proposal
Add Copyright page to the default frontmatter component options.
Design
Add 'Copyright page' below 'Cover' in the options.