Have terraform setup K8sProvider role

[frickjack]

and stop providing user aws keys as part of terraform config, and stop copying user aws keys to the k8s provider vm

From https://cdis.slack.com/files/U6R4GAN0H/F7Y018BQA/Setup_K8s_IAM_Roles_:

Currently we run kube-aws with personal AWS credentials that we upload to the kube provisioner via kube-up.sh:

mkdir -p ~/.aws
...
mv credentials ~/.aws

However - AWS allows us to assign a "role" to an EC2 instance which exposes temporary credentials to applications via a metadata service that the AWS SDK's (and kube-aws I'm pretty sure) hook into if credentials are not otherwise provided:

http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/iam-roles-for-amazon-ec2.html#instance-metadata-security-credentials
http://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_use_switch-role-ec2.html

For example - kube-aws assigns a role the the k8 nodes, so we can fetch a temporary key for that role by querying a node's metadata service:

$ kubectl exec gdcapi-deployment-3057747319-qpt77 curl http://169.254.169.254/latest/meta-data/iam/security-credentials/planxplanetv1-Nodepool-4VY43DV1ISHF-IAMRoleWorker-158QBVD5WMYA7
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 894 100 894 0 0 1064k 0 --:--:-- --:--:-- --:--:-- 873k
{
"Code" : "Success",
"LastUpdated" : "2017-11-09T22:01:42Z",
"Type" : "AWS-HMAC",
"AccessKeyId" :

First, I would like to extend terraform to assign a 'KubeProvider' role to the kube provider EC2 instance with admin permissions, and remove the code that installs the ~/.aws/credentials of whoever ran terraform, so that kube-aws and the aws-cli will run with the 'KubeProvider' role.