[TODO]: Core handler

[fu050409]

Branch Name: feat/core-handler

Description

Implement core handler for Quantumix server.

Expected Effect

Be able to exchange data stream by op code in json. Such as:

{
    "op": "project/new",
    "data": { 
        "name": "Moonstone",
        "description" "Instant messaging with end to end encrytion"
    },
}

This will add a new project Moonstone and save to database (This is just an example, the exact da model should desgin later).