[Enhancement] Add new option to drop items by their tier

[goflishMC]

This has 2 parts:

Part 1 This is an example of a drop table with the new option "tier-id"

name: '&dCommon Drops'
roll-once: true
level-penalty:
  enabled: false
  variance: 10
world-whitelist:
  - alleria
biome-whitelist:
  - '*'
region-blacklist: [ ]
items:
  common:
    chance: 100.0
    module-id: 'item_generator'
    item-id: 'random'
    tier-id: 'Uncommon'
    min-amount: 1
    max-amount: 1
    min-level: '1'
    max-level: '1'
    additional-conditions: [ ]
    actions-on-drop: { }

With this new feature we add a new option under item-id labeled "tier". Tier should default to "random" to give any tier.

Tier is currently set in the config.yml and each item file requires to input which tier the item belongs to.

Example Usage:

With item-id set to random and tier set to Uncommon, it would drop random items that only belong to the Uncommon tier.

Part 2 Add option to set module-id to "random"

Example Usage Set module id to random, set item-id to random, and tier to uncommon.

This would drop random items from all modules that belong to the uncommon tier.