Community staking

[olanod]

Creating communities requires registered users to back the creation with assets of some known value, initially that is KSM(the native token), in the future it could be with other assets or with "land"(smaller cells inside the community cell).

We want to encourage people to create communities and for that we have the fee collection system that sends transaction fees to the cell where the merchant is registered that are only usable once a community is founded, but as an extra incentive and to also incentivize users to register in a cell/upgrade their accounts they should be able to stake their KSM in the cell getting rewards as they would do in the relay chain. Here the difference being that the cell gets a percentage of the staking rewards. e.g. if relaychain rewards are 16%, a free cell takes 3% and 13% for the user or if the cell has a community it takes 1% for example to push people to form the community. If the percentage taken by the cell scares people away to rather stake in the relay chain this could also be the way to mint land tokens that might be given after a long enough period of time.

An extra note related to the registration of communities(https://github.com/virto-network/virto-node/issues/133), the reserved KSM in staking should be identifiable from other reserves in different pallets so we can check if the user has a enough to back the creation of the community, we can use the NamedReservableCurrency for that.