Updates to Giant Rats and Rat Ogres #97

1) Looks like the only place we can move it is to "No Category" and it
won't count against core points, but still count as points in the Army.
2) Found that it was not calculating correct number of Packmasters
based on the 1 for 5 rule.
3) Sqweel Gnawtooth points were not being calculated correctly. Should
be an upgrade like a champion for a packmaster, not a separate sections
for Giant Rates.
4) Issues with points 2 and 3 also apply to Rat Ogres.
5) I have also moved Sqweel Gnawtooth to the "Shared entries" section
so that the single model rule can be applied properly.