Closes #3450. 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