Large temple now only constructable after a difficult to afford tech in the temple has been researched.
Add tech for researching the large temple.

The tech is a bit difficult to afford for balancing the power of
converting priests:

- It will need quite a long time to research (500),
- females will be reluctant to gather food.meat anymore
(meat gather rate reduced by .1),
(because they have to feed all those priests),
- the healers' heal rate increases (by 1.5),

- Later it should also cost a certain amount of the favour of god resource.
Merge branch 'master' of https://github.com/0ADCoM/Aristeia