N2c local notification evolution to support `hasMore`

[jpraynaud]

Important

This is an idea of enhancement. This will create a breaking change and require coordinated modifications of DMQ node, Pallas library, Mithril nodes and CIP.

Support the hasMore flag in the n2c notification mini-protocol blocking request to allow returning not the full list of messages available.
The process would be:

• If the blocking request returns hasMore to true.
• The next call made by the client is a non blocking request.
• The previous steps repeats until the response includes hasMore to false.

This is related to the issue #15