SIP-24: SGT price incentives

We'd like to propose collective incentives to keep the SGT price high.

The collective incentives mean that everyone benefits from doing something, in our case we'd like to support the demand for SGT. We believe that these collective incentives will further support the value of SGT, they will help to get new investors and attract extra liquidity to the protocol. It also follows the "Shared" narrative we have at SharedStake.

The idea is to have 2 Moving Averages (fast & slow) and add extra staking rewards if the Fast Moving Average is higher than the Slow Moving Average. We propose to use 7-day MA and 30-day MA. The MAs can be built based on TWAPs/VWAPs.

On the other hand we don't want to raise the current reward rate, because we consider it pretty high already. Additional inflation can considerably decrease the token value which is bad for everyone. That's why we propose to decrease base rewards.

It's important to do these price checks at least once a week (a period of the fast MA). It also means we'll use the same period to raise the staking rewards for the upcoming days.

We're not going to increase rewards multiple times in a row. For instance,

Day 100: a 7-day MA is higher than a 30-day MA -> we increase the base reward rate by 40% for the next 7 days. Day 107: a 7-day MA is higher than a 30-day MA -> we keep the same reward rate (already increased by 40%) for the next 7 days. Day 114: a 7-day MA is lower than a 30-day MA -> we set the reward rate back to the base level (without extra 40%) for the next 7 days. Day 121: a 7-day MA is higher than a 30-day MA -> we increase the base reward rate by 40% for the next 7 days.

Option A to decrease base rewards by 20% and set the extra reward rate to 40%. Option B to decrease base rewards by 25% and set the extra reward rate to 50%. Option C to decrease base rewards by 15% and set the extra reward rate to 30%. Option D don't change anything.

Please keep in mind that we won't have extra rewards all the time. Let's keep the SGT price high together!