ADX: burn 2 million ADX from treasury in order to extend staking rewards

Currently, ADX has reached it's cap of 150M tokens. As such, staking rewards can no longer be distributed.

We propose that we extend the staking rewards by 2 million tokens, which at the current rate equates to 73 days:

2000000/ ((0x4668ee0c6f02be8 / 1e18)) / (246060) = 73

Those 2 million tokens will come out of the ADX treasury, meaning that 2 million ADX will be frozen/burned from the treasury to offset the new mint.

---

Additionally, we'd also like to propose another halving of ADX rewards rate, which will increase the period to 146 days.