[FeatureRequest] Uninstall hybrid Dev Envs

[janosmurai]

Revise the uninstall command to enable DEM to remove images from remote hosts.

Current Behaviour:
DEM can only uninstall local only Dev Envs. Meaning, it can only remove images that are locally available.

Expected behavior:
DEM should be able to remove images from remote hosts.
DEM should read the Dev Env descriptor and check the assigned tasks one by one. Based on the task definition locate the image location and remove it.
It's important that an image can be deleted only if no other Dev Env requires it.
Finally, go through all the images required by the Dev Env and remove the ones not referenced by any task (those are always local images only).
Set the Dev Env as 'uninstalled'.

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For axem internal use only:
Jira: https://axem.atlassian.net/browse/DEM-296