add new tool fix/archery-practice

[amade-w]

This is a new tool to temporarily mitigate the issue of ranged units not being able to practice at the archery range ('Soldier (no item)' issue). It scans inside the quivers of units in squads that are currently training, combines training ammo items until it reaches a stack size of 25, and drops any surplus ammo items on the ground so that each quiver will contain only one training ammo item.

An entry was added in internal/control-panel/registry.lua to execute this script every 449 ticks.

Limitation: unlike combine, this tool ignores item material, quality, and maker to simply combine whatever training ammo is contained inside the quiver.