devel/schilybase: do not install man pages, remove libstreamar

• man pages collide with base man pages and aren't very useful to the general user. Move them to a non-default MANPAGES option.
• remove libstreamar in preparation of moving it to archivers/star as it's used only there and its sole man page is kind of useful.

PR: 276825
Reported by: glebius