OpenAPI specs for API

[ilammy]

This is a preview version of OpenAPI (aka Swagger) specification of node API extracted from current documentation and source code. This machine-readable format is going to replace the current informal specification of the API in documentation.

It covers the following services:

• Exonum node management
• Exonum blockchain explorer
• BTC anchoring service
• configuration update service
• time oracle service

The content is rather crude, the descriptions are not fully complete, there are some spelling/grammar issues, some examples are missing. But it should be technically accurate for Exonum 0.9.0 (as in describing all endpoints, parameters, and results).

The API is currently not rendered anywhere. You can get a preview with online OpenAPI editor, just paste raw YAML content there. Please refer to those previews and provide feedback on what could be improved from technical standpoint.