Defining --no-dynamic-ip command line flag and NoDynamicIP member of …

[ElNounch]

…struct CreateArgs

[moul]

Related with #283, @QuentinPerez can you check both pull-requests at the same time ?

[QuentinPerez]

Hi @ElNounch thank you for your PRs

With this solution, we have a conflict between --no-dynamic and --ip-address

$> ./scw create --no-dynamic-ip --ip-address='212.47.226.27' ubuntu-wily
$> ./scw inspect 00000000-0000-1000-0000-000000000000| jq '.[0].public_ip'
{
  "id": "00000000-0000-1000-0000-000000000000",
  "address": "212.47.226.27",
  "dynamic": false
}

Personally, I prefer this solution #283, I think that it is more readable and does not add complexity

[QuentinPerez]

We have merged #283 instead