REST API for Peerplays Blockchain APIs

[bobinson]

User Story
A REST API layer as discussed in bitshares/bitshares-core#870 or the Steem Hivemind layer is required for Peerplays. The Demux approach in EOSIO can also be considered (https://github.com/Zapata/demux-js-bitshares)

Impacts
In the long term, with many dApps under development the full API nodes will come under heav load. A REST API layer with caching can be helpful to mitigate this scenario.

Impacts
Describe which portion(s) of Peerplays that may be impacted by your request. Please tick at least one box.

• API (the application programming interface)
• Build (the build process or something prior to compiled code)
• CLI (the command line wallet)
• Deployment (the deployment process after building such as Docker, Gitlab, etc.)
• P2P (the peer-to-peer network for transaction/block propagation)
• Performance (system or user efficiency, etc.)
• Protocol (the blockchain logic, consensus, validation, etc.)
• Security (the security of system or user data, etc.)
• UX (the User Experience)
• Other (please add below)

Community / PBSA check list

• Evaluate / Prioritize Feature Request
• Refine User Stories / Requirements
• Define Test Cases
• Design / Develop Solution
• Perform QA/Testing
• Update Documentation