Add support for the lottery module

[jacogr]

[rrtti]

Adding my thoughts on this:

• the UI should allow users to see which lotteries are active and which calls are included (itll be one lottery per period (28 days) so it might make sense not to have a separate tab for this i think.
• council members should be able to pass a lottery proposal for vote in council on the same page, specifying which call will be participating. the lottery (similar to bounties) should track status, votes, and active or closed.
• maybe it makes sense to announce the winner next to the lottery once its closed and enable a button to claim the prize.
• a button should be added on the signing window of Apps allowing users to enable the purchasing of a ticket for the active lottery.

I will think a bit more on this and add anything ive missed.

cc @shawntabrizi

[ltfschoen]

wouldn't this require licensing (casino, commercial gambling, insurances)?

i mentioned similar concerns here https://zeitgeist.subsquare.io/post/11