Add getInflationRate for reward and dynamic reward modules

[shuse2]

Description

Add getInflationRate endpoint for both Dynamic reward and reward modules.
The rate should be number of token scheduled to be generated / year.
The number of token scheduled to be generated should consider

• current reward bracket
• 365 days for a year
• block time

Req

{}

Res

{
  tokenID: string,
  rate: number,
}

Acceptance Criteria

• Add unit tests for each brackets of the reward

Additional Information

• We have consider to make the inflation rate more accurate, but this information is only used as supplemental information for user, and it will not be accurate information because reward changes based on the protocol violation. Therefore, it only consider current bracket for the estimation