make Ownership make sense wrt toolkit & improve smls output

Hacking on the SM toolkit. Realized the way Ownership works right now is making the paths nonsensical. As a minor optimization, I made Ownership::get() lop off the first X directories in the path b/c they would all be the same (/usr/local/mariadb/columnstore) theoretically. Not creating / storing / traversing those extra directories is a small time saver across the system.

However, when using the toolkit, you now have to prepend a bunch of nonsense directories. ex, 'smcat /1/2/3/4/file' instead of 'smcat file'.

The output of smls also needs to be changed s.t. the only files returned by the listing are .meta files. If it doesn't have a .meta extension and is not a directory, it should be left out of the output.

Another consideration wrt Ownership. If the toolkit is used on a node that doesn't own the specified prefix, and the storagemanager dirs are on a shared FS, the tool will grab ownership to perform the operation. Ex, running 'smls dir-owned-by-another-node' will take ownership temporarily. Need to think about how these concepts should coexist.