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To whomever attempting this: Have fun.
Proof of concept for tabwidget template

TabContainer, headlines automated, dynamic attribute access

TODOs: RenameLabel support, icons below minimap (left/right area)
Add settlement.name property

This is a shortcut to its NamedComponent, intended for use with the new
TabWidget, but hopefully not limited to that.
Add inhabitant name property for tier overview tabs at main square
Remove WarehouseOverviewTabs from warehouse, storage

Those had almost no content and were too small to display all tab
buttons in their tab area. Now sporting account tabs instead.

This also changes the icon of AccountTab to the overview tab one!
tabwidget: Rewrite and relayout mainsquare_inhabitants
tabwidget: Rewrite and relayout overview_{signalfire,tower}

Two proof-of-concept tab conversions.
tabwidget: Rewrite and relayout editor_settings

This also adds some explanatory labels and an actual heading.
tabwidget: Rewrite and relayout overview_tradership
tabwidget: Rewrite and relayout overview_enemy{building,unit,warehouse}

Entirely removes the currently redundant overview for enemy units.
To be added at a later point where such units' information displayed in
those tabs is actually different from enemy buildings.
tabwidget: Rewrite and relayout overview_firestation
tabwidget: Rewrite and relayout overview_resourcedeposit
tabwidget: Rewrite and relayout overview_settler
tabwidget: Rewrite and relayout overview_productionbuilding
tabwidget: Rewrite and relayout boatbuilder
tabwidget: Rewrite and relayout diplomacy
tabwidget: Rewrite and relayout island_inventory

This needs more love for the dynamic background icon generation still.
tabwidget: Rewrite and relayout overview_select_multi
tabwidget: Rewrite and relayout overview_{trade,war}_ship
tabwidget: Rewrite and relayout tradetab