WIP: Try to properly filter static libraries
Adds a global split rule for static libraries, which is filtered out of the desktop stack in
desktop-filter-static.bst. The static libraries we explicitly want to include are re-introduced into platform image by
static-libraries.bst, which introduces a
static-whitelist domain for split rules. Adding libraries to the whitelist is just a matter of adding them to this domain in this element. I think this should work correctly, but I may need to rework where the filtering happens to avoid leaking libraries through.