(CFACT 92) Support for memory facts for solaris

This patch adds support for system memory facts for solaris. It uses the
kstat library to fetch the total and free RAM available, and the swapctl
for swap memory information.
How does this work?  I suspect it's only looking at the first entry based on the definition of swaptbl_t.  We should probably be iterating like we do when setting up `ste_path` on each entry.