Добавить возможность конфигурации инстансов в разрезе серверов

[kdy999]

Пример конфига:

---
instances:
  - name: storage
    masters_cnt: 2
    weigth: 10
    config:
      memtx_memory: 134217728
  - name: router 
    masters_cnt: 2

vars:
    cartridge_bootstrap_vshard: true
..
    cartridge_failover_params:
      mode: eventual
    cartridge_defaults:  # default instance parameters
      memtx_memory: 67108864
      
hosts:
  vagrant:
    ports:
      begin_http: 8081
      begin_binary: 3301
    host_1: 192.168.101.166
      config_replicasets:
        weigth: 3
        config: 
          memtx_memory: 1000000
    host_2: 192.168.101.167