Add option to punish defenders with inventory loss when they are losing by too many points.

[LlmDl]

Description:

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New Nodes/Commands/ConfigOptions:

  - keep_inventory_on_siegezone_death.disable_for_defenders.enable
    - Default: false
    - This feature, when enabled, will cause defenders to not keep their inventory if the Siege point balance is too far positive.
    - ie: They defenders are losing by a great number.
  - keep_inventory_on_siegezone_death.disable_for_defenders.threshold
    - Default: 500
    - The threshold required to cause defenders to lose their inventory. If the Siege point balance is equal to or greater than this number
      and disable_for_defenders is enabled, defenders will not keep their inventories.

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Relevant Issue ticket:

Closes #919

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• [ ] I have tested this pull request for defects on a server.

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