Add references of u-u Remove-Unused-Kernel-Packages setting

[tonyskapunk]

• Add ref about u-u's Remove-Unused-Kernel-Packages setting

Fix #79

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@rbalint do you mind looking at the changes? Let me know if they read well now. Thanks!

[tonyskapunk]

@rbalint thanks for the time and feedback, I've made those changes. If everything looks then I'll merge this one.

[rbalint]

@tonyskapunk Thanks, looks good now!