Enable and configure the maximum change rate adjustment feature for vToken exchange rates

| vToken | Expected APY | Period(Block) | Maximum Change Rate Limit |
|--------|--------------|--------|--------------------------|
| vDOT   | 12.00%       | 14400  | 0.0986%                  |
| vETH   | 2.80%        | 14400  | 0.0230%                  |
| vBNC   | 5.00%        | 14400  | 0.0411%                  |
| GLMR   | 10.00%       | 14400  | 0.0822%                  |
| vASTR  | 15.00%       | 14400  | 0.1233%                  |
| vMANTA | 10.00%       | 14400  | 0.0822%                  |


vToken exchange rates configuration

candidates

members

proficients

fellows

senior_fellows

experts

senior_experts

masters

senior_masters

grand_masters

root

whitelisted_caller

fellowship_admin

referendum_canceller

referendum_killer

liquid_staking

system_staking_admin

salp_admin

treasury_spend

delegated_voting_admin

vToken	Expected APY	Period(Block)	Maximum Change Rate Limit
vDOT	12.00%	14400	0.0986%
vETH	2.80%	14400	0.0230%
vBNC	5.00%	14400	0.0411%
GLMR	10.00%	14400	0.0822%
vASTR	15.00%	14400	0.1233%
vMANTA	10.00%	14400	0.0822%