Remove the build time malus from Greek civ bonus.

The 'Hellenic Architecture' bonus for Greek civilisations increased health and capture points slightly, but also build time.
Because it is active from the start, it ended up being a large economic debuff that made these civilisations less competitive.

The build-time increase is removed so "Hellenic Architecture" is now a pure bonus.

Patch by: Feldfeld

Accepted By: wraitii, borg-

Differential Revision: https://code.wildfiregames.com/D2839