REST API [#3450]

Closes #3450 (closed). Implements a REST API with the following endpoints:

• GET /query/:id
• GET /query/:id/chain
• GET /query/:id/chain/:name
• GET /query/:id/chain/:name/index/:index
• GET /query/:id/chain/:name/entry/:entry
• GET /query/:id/data
• GET /query/:id/data/index/:index
• GET /query/:id/data/entry/:entry
• GET /query/:id/directory
• GET /query/:id/pending
• GET /block/minor
• GET /block/minor/:index
• GET /block/major
• GET /block/major/:index
• GET /search/:id/anchor/:value
• GET /search/:id/publicKey/:value
• GET /search/:id/publicKeyHash/:value
• GET /search/:id/delegate/:value
• GET /search/:id/messageHash/:value
• GET /node/info
• GET /node/services
• GET /consensus/status
• GET /network/status
• GET /metrics
• POST /submit
• POST /validate
• POST /faucet

Changelog: feature