Don't show default tools trees in the summary

Don't show default tools trees in the summary

Instead, let's show individual tools tree packages in the summary.
This makes things a bit more consistent as we don't show default
initrd presets in the summary either (and making that happen is no
trivial task so we opt to do the reverse and not show default tools
trees either).

We also add a table to the documentation showing which packages are
in the default tools tree for which distributions.