Create Docker containers with all the swift dependencies

[ematejska]

Imported from JIRA https://bugs.swift.org/browse/TF-565

Type:	Task	Priority:	Minor
Reporter:	Gogul Balakrishnan	Assignee:	Unassigned
Resolution:	Unresolved	Votes:	0
Labels:	None

Right now, the DockerFiles for all tests install the dependencies before running any tests. The installation takes most of the time for a CI run. e.g., https://github.com/tensorflow/swift-apis/blob/55adef7/Dockerfile

We should create a docker container with all the dependencies already installed so that the DockerFile for CI can simply be as follows:

FROM gcr.io/swift-tensorflow/swift-for-tensorflow-ubuntu-18.04-cuda-xx-cudnn-xx 
<download testee repo>
<run tests>

It would also be convenient for anyone who wants to quickly download a working s4tf dockerfile