deskutils/bookworm: Add new port

Bookworm is a simple, focused eBook reader.

Read the books you love without having to worry about the different
format complexities like epub, pdf, mobi, cbr, etc. This version
supports EPUB, PDF and Comics (CBR and CBZ) formats with support for
more formats to follow soon.

WWW: https://babluboy.github.io/bookworm/

Reported by: 0mp
Differential Revision: https://reviews.freebsd.org/D25569