OSModifier: Add selinux support

[elainezhao96]

Merge Checklist

All boxes should be checked before merging the PR (just tick any boxes which don't apply to this PR)

• [ ] Ready to merge

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Summary

What does the PR accomplish, why was it needed? Add selinux support in osmodifier

Change Log

• add handle selinux logic in osmodifier (basically what the handleSElinux without reset ResetbootLoader) , this will help replace https://dev.azure.com/mariner-org/ECF/_git/trident?path=/osutils/src/grub.rs&version=GBmain&line=61&lineEnd=62&lineStartColumn=1&lineEndColumn=1&lineStyle=plain&_a=contents in trident

Does this affect the toolchain?

NO

Testing

Will test it in trident