Add timeout period as a command line option for run_async_query #55

A part of the async transactions protocol we're building is the keepalive feature. It basically means if the client did not poll a given transaction using a GET request within a period of time, this transaction will be scheduled to be cancelled.
The first step to implement this is to have this timeout period a field that gets set by the client as a command line option.

Discussed on January 14, 2022:

• The unit should be minutes
• The default values should be:
  • Read: 1m
  • Write: 0, which means do not time out