Refactor the network model

[billlyzhaoyh]

• bump up the version to the latest of SEIRPLUS and use the latest functionality
• change the way control/scenario parameters are read in (instead of csv we want to use a config file)
• new intervention like testing to be built in (less Moria specific as currently there are only two interventions in there)
• stochastic run of 20-30 for one scenario