Implement LEGENDS expansion

[lilasquared]

What's your idea / feature request?
It would be great if this included the LEGENDS expansion. I am willing to work on it!

Is your feature request related to a problem or pain point?
nope

Describe the solution you'd like
Implementing the 10 LEGENDS cards and mechanisms for

• dealing them out at the start of the game (without taking up a space in your hand)
• playing them from their upgradable card or cost
• adding an additional free space in your city once you've played them
• discarding the upgradeable card

[ymichael]

hi!! we weren't aware of this expansion until you created this issue! definitely open to accepting PRs for this if your down to do the work

[lilasquared]

I am happy to take a crack at it!