refactor all the api, offer a new syntax (BC broken)

The version 0.5 will be a completely re-factored version with a new Client class added.

The purpose is to separate concerns and apply the KISS principle.

• Move Endpoints handling from documents.peer module to a new api.endpoint module.

• Create a new ws2p dedicated package.

• Create a new elasticsearch dedicated package.

Write a new Client class to simplify connection syntax.

Example :

    BMAS_ENDPOINT = "BMAS node.domain.org 443"

    # Create Client from endpoint string in Duniter format
    client = Client(BMAS_ENDPOINT)

    # Get the node summary infos by dedicated method (with json schema validation)
    response = await client(bma.node.summary)
    print(response)

    # Get the money parameters located in the first block
    response = await client(bma.blockchain.parameters)
    print(response)

    # Get the current block
    response = await client(bma.blockchain.current)
    print(response)

    # Get the block number 10
    response = await client(bma.blockchain.block, 10)
    print(response)

    # jsonschema validator
    summary_schema = {
        "type": "object",
        "properties": {
            "duniter": {
                "type": "object",
                "properties": {
                    "software": {
                        "type": "string"
                    },
                    "version": {
                        "type": "string",
                    },
                    "forkWindowSize": {
                        "type": "number"
                    }
                },
                "required": ["software", "version"]
            },
        },
        "required": ["duniter"]
    }

    # Get the node summary infos (direct REST GET request)
    response = await client.get('node/summary', rtype=RESPONSE_AIOHTTP, schema=summary_schema)
    print(response)

    # Close client aiohttp session
    await client.close()