[CHE 6] Implement different strategies of PVC for OpenShift infra

[akorneta]

Now all workspaces in one OpenShift project store projects sources in one PVC which name is configured. It was implemented in this way to do the same as OpenShift connector does. And it works fine for OSIO flavour because of its resources limits where user has one and only one PVC for storing of projects sources.
In case of using one PVC for storing projects sources of all workspaces there can be only one started workspace, and it is not good enough for OCP flavour.
For OCP flavour it is required to have an ability to configure this strategy and choose where workspaces projects sources should be stored. So we'll have the following strategies:

1. One PVC for all workspaces in one OpenShift project. Its name is configured. (This is implemented behavior). This strategy allows to start only one workspace correctly.
2. One PVC for One Workspace. In this case we can name PVC for each workspace like che-ws-data-{WORKSPACE_ID}. This strategy allows to start as many workspaces as user wants.