This PR adds the base tags to DHCP Options, IGW, and Route Tables.
These components are not tagged correctly, and this can cause issues
with deletion. Name tags are not added to shared resources, as we allow
shared resources to have maintained names. A owned/shared tags with the
syntax "kubernetes.io/cluster/$CLUSTERNAME" = "owned" is added to the
resources as well. We are maintaining the Name tag value for private
route tables, as these resources do not use the standard value.
Beginnings of a mock for the AWSCloud, so that hopefully we aren't
calling out to AWS at all in the tests. We will likely start mocking
the actual EC2 APIs in future, but this seems a good starting point.
Fix#425