Logistics improvement (p.2/2) Tunnels and Canals

Modern logistics play a big role in modern commerce and warfare.
The second big part of my transportation buff proposal are tunnels and canals.

I suggest adding 2 new types of districts - tunnels and canals. Would be great to allow them to be multi-hex, for which a special "hex paint tool" would be needed.
- Upon wanting to build a tunnel or a canal the player should be able to paint several mountain tiles for tunnel or several non-mountain tiles for a canal. Tiles with main plaza, administrative center or world wonder can't be painted.
- The tunnel or the canal should start and end at a valid exit point within a single city (but can span across multiple territories).
- Each painted tile increases industry/money cost of the tunnel/canal. And in case of canal, the altitude of painted tiles also affects the cost.

- Army/Fleet need to have more than half of the maximum movement points to use a tunnel/canal, it consumes all the remaining movement points and teleports the army/fleet to the other side. If the tile on the other side is occupied, using the tunnel/canal is impossible.
- Quarrying industry infrastructure should give industry cost discounts on building tunnels/canals.
- Tunnels and canals can be used by trade routes, and tunnels allow both roads and railroads to pass through them.