Balance economy techs to make City Phase less of a snowball.

City Phase economic technologies gave +50% gathering rate increases, on top of the pre-existing ones, which was such a huge bonus that players could never recover from being late.

This patch balances techs so that Village and Town phase technologies are stronger, and City phase not so potent.
Research times also increase with each phase.

Patch by: borg-

Reviewed by: wraitii, badosu

Differential Revision: https://code.wildfiregames.com/D2916