By putting more javascript into the static plansblock.js file, it's
possible to remove the script element from the template.  This is
better for exports, which should not include javascript designed for
the site.  Putting the entire block initialisation into a separate
function also allows the pagination links to be made available when a
new plans block is first dragged into a page.

Change-Id: I7a5e6448c14272660b317b55b4db7cd2829576f7
Signed-off-by: Richard Mansfield <richard.mansfield@catalyst.net.nz>