Access control documentation: Linkify conversion table

This patch adds links to the respective categories referenced in the
2.1.x -> 2.2.x conversion table, hopefully making it more usable when
trying to learn the new permission model.

Also; Push Tag +3 never existed in 2.1.x, it is now replaced in the
table with the old actual way to do it.

Change-Id: I1bc5b0746f9383154b13ba4ae51830c778349d8a
Signed-off-by: Fredrik Luthander <fredrik.luthander@sonyericsson.com>