meson.build: Also use CMake to help find OpenSSL

... on Visual Studio-like builds, as CMake has built-in support for
looking for OpenSSL 0.9.8+ on Visual Studio.  Make sure that everything
is there by specifying `modules` in the dependency() call.

This should clean up meson.build quite a bit for OpenSSL.

Part-of: <https://gitlab.gnome.org/GNOME/glib-networking/-/merge_requests/206>