Tokenomics updates Phase 2: REX 2.0

```[tasklist]
### Tasks
- [ ] https://github.com/eosnetworkfoundation/eos-system-contracts/issues/133
- [ ] https://github.com/eosnetworkfoundation/eos-system-contracts/issues/118
- [ ] https://github.com/eosnetworkfoundation/eos-system-contracts/issues/134
```
