Add RPC calls for Farmer and Harvester

[MadddinTribleD]

Add RPC calls for Farmer and Harvester

• Farmer
  • public async getSignagePoint(signagePointHash: string ): Promise<SignagePointResponse>
  • public async getSignagePoints(): Promise<SignagePointsResponse>
  • public async getRewardTarget(searchForPrivateKey: boolean): Promise<RewardTargetResponse>
  • public async setRewardTarget(farmerTarget?: string, poolTarget?: string): Promise<RpcResponse>
• Harvester
  • public async getPlots(): Promise<PlotsResponse>
  • public async refreshPlots(): Promise<RpcResponse>
  • public async deletePlot(fileName: string): Promise<RpcResponse>
  • public async addPlotDirectory(dirName: string): Promise<RpcResponse>
  • public async getPlotDirectories(): Promise<PlotDirectoriesResponse>
  • public async removePlotDirectory(dirName: string): Promise<RpcResponse>

Taken from Chia-Network/chia-blockchain/wiki/RPC-Interfaces and code under chia/rpc/farmer_rpc_api.py and chia/rpc/harvester_rpc_api.py

Closes #2

[freddiecoleman]

Thank you for the contribution!