Show topology pane in per-display fragment

Some changes made to the UI, i.e. presence or absence of items, based on
feedback. There is some ambiguity because we are not fully v2 yet, hence
this change.

When all external displays are attached after opening the fragment, we
now show no preference items, whereas before we showed the pane with
built-in display options.

If only one external display is attached, we skip the "display list"
version of the fragment, and instead show the pane and other v2 items in
the per-display fragment.

If 2 or more external displays are attached, we do not show the pane
after selecting a display, which makes the rotation/resolution items
easier to find. I tried to get scrollToPreference to work but could not,
and it could be a little disorienting anyway.

To help manage the growing number of setOrder calls, keep the order
values as well as other pref data in a single spot. This also reduces
the amount of boilerplate around constants needed and makes uniform how
multiple preferences are built.

Flag: com.android.settings.flags.display_topology_pane_in_display_list
Bug: b/366056922
Bug: b/394361999
Test: TODO
Change-Id: Iaa33f6d9220a1658a372c0432fe159a69dbb88a5