minimize RAM usage of disk uploader when extracing big disks

[codingben]

There can be big disk images. The size of them can be 10-100gb (e.g. in Windows VMs). May be need to perform scalability testing in order to ensure that existing functionality can deal with big disk images.

@akalenyu said that CDI is using below 1gb of RAM to import disk images from container registry, and in our case, it could be also applied.

[codingben]

Currently disk-uploader requests 3gb of memory and limits it to 5gb.

[kubevirt-bot]

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[codingben]

/remove-lifecycle stale