The packages concept came from the old wiki. It more or less duplicates the
content listed in the "Platform APIs and Services" architectural document, but
also lists a number of packages that have long since been removed from Apertis.
Perform a quick tidy up, moving any potentially useful/relevant information to
the architectural document and deleting the packages page.

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>