Motion 229 increase the number of validators by 1 every era (6hs) for 100 eras.

The motion was opened since referendum 88 passed but was not able to be executed (for using after: 0 instead of after: 1). I proposed the motion at luckyve's request and given the referendum passed, until we can test and use the damping function. For this reason as well as for the numbers of waiting validators, I proposed a repetition of 100 instead of 400, as originally proposed.