Create base TPU image
🚀 Feature
Create a base Docker image with TPU requirements and all PL dependencies - base + extra
Build this docker with a week crone and push to PL docker hub...
Motivation
Speedup TPU tests, because the repetitive build takes about 7min
Pitch
It could be used also by other developers
Additional context
See Docker build workflow - https://github.com/PyTorchLightning/pytorch-lightning/blob/master/.github/workflows/docker-builds.yml