emulators/ppsspp: update to 1.19.1

While here:

• fix hang when using vulkan graphics backend. This is due to FreeBSD mesa- ports, currently on version 24, only supporting vulkan api version 1.3.
• add BSD3CLAUSE to LICENSE and LICENSE_FILE.
• remove defunct 2014 Debian man page. The fetch link for the man page is broken. There's no longer a ppsspp package for Debian.

Changelog: https://www.ppsspp.org/news/release-1.19/

PR: 287409
Reported by: Kevin Reinholz <kreinholz@gmail.com> (maintainer)