Different soldier types have different attacks. This patch therefore moves the attack sound groups to the template where the attack damage is actually defined, rather than having it in their grandparents. This is already the case for many (e.g. javelineers, spearmen).
Also moved the <attack_slaughter> sound from `template_unit.xml` to only its three children that have <Attack/Slaughter>.
[EDIT] Further changes:
* Cleaned up sounds in `*fauna*` templates.
* Cleaned up sounds in `template_unit_support_*` templates.
* Gave `maur_elephant_archer_b.xml` and `maur_support_elephant.xml` the same sounds as `template_unit_champion_elephant.xml` and `template_unit_hero_elephant_melee.xml`, except for <attack_melee>.