Add support for ExtraPartitionSize to address issue #676

[xphyr]

Background / Context

This PR addresses the inability to reserve some space on the install device for other partitions. By allowing for additional partitions on the install disk we can create partitions for use by other processes, such as the LVM Operator.

Issue / Requirement / Reason for change

This PR addresses issue #676

Solution / Feature Overview

I have added one extra configuration option "ExtraPartitionSize" which allows you to define the size of the varlibcontainers partition that is created. It is a optional configuration. If you do not define this option, the lca-cli works exactly the same as it did prior to this code change. This means that all existing configuration files will work with no changes.

Implementation Details

This change takes advantage of the existing "sgdisk" code and appends the required additional value of ExtraPartitionSize to the "new" command, allowing us to specify a total size. By defaulting "ExtraPartitionSize" to "0" the any previous config files that did not specify this value will work without any modification.

Other Information

Given that MCO can not be used to configure additional partitions the lca-cli utility should be updated to support the creation of additional partitions as part of the image application process. In theory this can be handled by adding a "post.sh" with the additional commands, but it would be easier if it was built into the utility itself.

[openshift-ci]

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[openshift-ci]

Hi @xphyr. Thanks for your PR.

I'm waiting for a openshift-kni member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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