GPU for ML model training in K8S

[kirillmakhonin]

As a creator of ML models, I want to have an ability to train my models using GPU instances. It will reduce time and cost of model training in some cases.

Not everyone train requires GPU, so optional flag (like gpu: true) for ModelTraining Entity will be good solution for my requirements.

Subtasks:

• Add support of using GPU on AWS K8S (EKS) #920 - Add support of using GPU on AWS K8S
• Add support of using GPU on GKE #921 - Add support of using GPU on GKE
• Add support of requiring GPU in ModelTraining entity #922 - Add support of requiring GPU in ModelTraining entity
• Add examples with models that require GPU and add tests for them #923 - Add examples with models that require GPU and add tests for them

[kirillmakhonin]

Awaiting for new training mechanism #930