Multi-session support for msf and sliver

[whotwagner]

It would be nice to have a unified method for creating multiple connections for api's. Currently the configs for sliver and msf are:

msf_config:
  password: securepassword
  server: 127.0.0.1

sliver_config:
  config_file: /home/attacker/.sliver-client/configs/attacker_localhost.cfg

A named approach could be:

msf_config:
  server1:
    password: securepassword
    server: 127.0.0.1

  msf2:
    password: securepassword
    server: 127.0.0.2

sliver_config:
  sliver_server1: 
    config_file: /home/attacker/.sliver-client/configs/attacker_localhost.cfg

  sliver_server2:
   config_file: /home/attacker/.sliver-client/configs/attacker2_localhost.cfg