(Reference Suite) Fetch teambonus auras from player_{civ}.xml files
(The civ key (in the team bonus aura templates) was added in rP24492 for the
purpose of identifying which aura belongs to which civ. It's no longer used.)
Proposed by: @Nescio
Comments by: @Freagarach
Refs: r24492
Differential Revision: https://code.wildfiregames.com/D3864