Added Missing AWS IAM Profiles and Policies

The AWS IAM profiles and policies required to run Kargo on AWS
are no longer hosted in the kubernetes main repo since kube-up got
deprecated. Hence we have to move the files into the kargo repository.

contrib/aws_iam/kubernetes-master-policy.json

@@ -0,0 +1,27 @@
+{
+  "Version": "2012-10-17",
+  "Statement": [
+    {
+      "Effect": "Allow",
+      "Action": ["ec2:*"],
+      "Resource": ["*"]
+    },
+    {
+      "Effect": "Allow",
+      "Action": ["elasticloadbalancing:*"],
+      "Resource": ["*"]
+    },
+    {
+      "Effect": "Allow",
+      "Action": ["route53:*"],
+      "Resource": ["*"]
+    },
+    {
+      "Effect": "Allow",
+      "Action": "s3:*",
+      "Resource": [
+        "arn:aws:s3:::kubernetes-*"
+      ]
+    }
+  ]
+}