Add ability to configure ephemeral mode for workspaces from dashboard

[ashumilova]

There is attribute, that allows to configure workspace to be ephemeral with no PVC attached on K8S/OpenShift infrastructure, so the aim of the issue is to allow configure that attribute from UI of User Dashboard.
Attribute name is persistVolumes, that shoud be set in workspace configuration.

[slemeur]

Can be on the workspace overview page.

[sleshchenko]

@ashumilova Should we close it since the corresponding PR is merged?

[ibuziuk]

@ashumilova @slemeur @l0rd is it planned to add ephemeral trigger to the create-workspace view ? currently IMO it is hidden and as I understand we want to encourage / make default ephemeral workspace creation (at least on che.openshift.io)

[slemeur]

@ibuziuk : I don't think it should be done in upstream.
We should have a dedicated task to handle that for the case of che.openshift.io.

[ibuziuk]

hmm... but why not to add the toggle (disabled by default) in the upstream, and just enable it by default in downstream ? IMO it is really logical and I guess it was smth. we have discussed with @l0rd (or maybe I got wrong idea)