Maximum number of active validators at any moment.
We do not allow the number of validators in any epoch to go above this.
Lower-bound on the amount of stake required to become a validator.
A validator can have stake below validator_low_stake_threshold
for this many epochs before being kicked out.
Validators with stake amount below validator_low_stake_threshold
are
considered to have low stake and will be escorted out of the validator set
after being below this threshold for more than
validator_low_stake_grace_period
number of epochs.
Validators with stake below validator_very_low_stake_threshold
will be
removed immediately at epoch change, no grace period.