libcasper: Move everything to the libcasper package

[ivy]

Summary

The libcasper package exists to contain libcasper, but for some reason,
only the libcap_net service was in the package, with libcasper itself
and the rest of the services being in runtime. Move everything to the
libcasper package, except tests, which stay in the tests package.

MFC after: 1 day

[emaste]

AFAICT what happened is:

• the casper services mostly predate the introduction of pkgbase packages, and ended up in runtime
• @oshogbo added cap_net and (reasonably) put it in a libcasper package but other services were not moved
• cap_netdb was added, probably with a Makefile copied from some other existing service

Will runtime need a dependency on libcasper now?

[ivy]

In D53576#1223087, @emaste wrote:

Will runtime need a dependency on libcasper now?

yes, since several things in runtime use libcasper, but i don't think that's an issue: runtime already has several similar shlib dependencies.