Proposal: Oracle V2 reporting sanity check parameter values

Future Oracle upgrade (https://research.lido.fi/t/oracle-contract-upgrade/500) brings new sanity checks to the reporting. Namely, the code prevents reporting big and sudden changes in ETH2 stake. There are checks for “stake increments with too big APR” and “instant stake drops”. We propose to set the boundaries for the checks to 10% and 5% respectively. Note that those parameters can be adjusted later by the DAO vote, but Oracle v2 needs those numbers set from the start.

More details about sanity checks and params can be found in the LIP-2 “Oracle contract upgrade to v2”: https://github.com/lidofinance/lido-improvement-proposals/blob/develop/LIPS/lip-2.md#sanity-checks-the-oracles-reports-by-configurable-values