Proxy server-client structure for resolving ARTIQ dependency and asynchronization

[BECATRUE]

Whlie we developed this project, we faced two main problems:

1. ARTIQ dependency
   In the current system, we use several ARTIQ commands (e.g., artiq_client).
   But, it demands that we should install ARTIQ in our local environment and it is a big restriction.
   Futhormore, we need to use a few non-existing functions of ARTIQ command line which are implemented only in ARTIQ internal system, so that we should implement a new RPC manager.

2. Asynchronization
   Basically, ARTIQ uses an asynchronous communication.
   However, qiwis doesn't support asyncio, so we need to handle it in each app of iquip.

Thus, we decided implementing a proxy server in the PC which connects to ARTIQ directly and access the proxy server from our private PC as a proxy client.

The main functions of the proxy is are follows:

1. RPC manager
   It will be run as a RPC manager like artiq_client.
   Whenever a client sends a reqeust, it receives and transmit it to artiq_master.
2. Make iquip async-independent
   It makes iquip project independent for asynchronous communication.
   Then, we can use RPC functions as a synchronous function.

We will make it as another project called artiq-proxy.