Add support for suite components to mmdebstrap plugin

[dilyn-corner]

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Request

Describe the feature you'd like to see implemented.

Support an option such as mmdebstrap-components: [main, universe, ...] for the mmdebstrap plugin.

The problem it solves

Describe the impact your request would have.

Some packages one may wish to be included in an image (or are even required for the image) may only come from universe or gasp restricted. Because the mmdebstrap plugin does not support specifying components, only the main component is added to the rootfs and so the method for bootstrapping a rootfs prior to the existence of this plugin must continue to be used.