stateful module to manage EIPs, added vpc connector

Module to state-fully manage Elastic IPs. 
Required arguments include vpc_id and hostname.
Create EIP:
```
  - name: Create EIP
    local_action:
      module: ec2_eip_eni
      state: present
      vpc_id: "vpc-123456"
      fqdn: "webserver1.dev.example.com"
    register: eip
```
It will create elastic network interface and in it's tags will store information about EIP.
EIP will not be associated to ENI and ENI will only be used to store the metadata information.