Increase city strength (Closed)

[HaneulCheong]

• Increased city strength
  • Pseudocloses the first part of https://github.com/SpacedOutChicken/DeCiv-Redux/issues/31#issuecomment-1064094366.
  • In short, Initial city strength is now on par with that of a Spearman.
  • Base city strength increased from 8 to 20.
  • City strength per pop increased from 0.4 to 0.5.
  • Bomb Shelter now gives 5 city strength instead of 2.
  • Made early-game rushes much harder while still allowing aggressive late games.
  • Also fixed a typo in Buildings.json.
• Hid Flood plains
  • Closes #21.
  • Flood plains are now hidden from Civilopedia since they will not spawn until a rework is done.
• Fixed snow farm using vanilla tileset
  • Snow farm without hills now uses DeCiv's tileset.
  • Also fixed my mistake in 6a0906f16a20fab48011c8f288714f27a65f11df:
    I forgot that multiple trailing spaces in markdown is a line break...

[SpacedOutChicken]

This is looking pretty good.

[HaneulCheong]

That was embarrassing... Anyway, fixed some conflicts.

[HaneulCheong]

I'll just push another PR...