Rune System

Overview
Runes are objects that can be placed on equipment

They can be changed at any time to allow flexible build

Inventory is shared across characters

Runes come in different Tiers. Each Tiers of a rune has the same effects but the strenght of this effects gets better the higher the tier is (Crit chance T1 = +5%, Crit chance T3 = +15%)

There are different types of runes : Each equipment has a different number of rune slots available. Each slot accept only a specific type of rune (maybe more than one in specific cases? TBD)
 * Offense
 * Defense
 * Utility
 * Magic
 * TBD

Design Benefits
The rune system would go along a removal of damage scaling on weapons and armors. There will be no scaling on equipment strenght along the run. The scaling of damages and defense will rely on looting better runes and upgrading character's stats (can also be done through rune equipment)

This means:
 * Equipments will be more unique: No redundancy when looting the same weapon but just stronger
 * Equipments will not go obsolete: No need to change equipment just because a new one has a better level
 * No need to make players loot ton of equipment: Equipment can now be looted on specific occasions like boss fights and chest since a part of the character's growth in power will be done through rune

Runes will be looted commonly accross the run to allow for lots of build options. The type of item "Rune" will be one more system for us to interact with. Some random ideas are:
 * Upgrading runes: Sacrifice lesser tier runes to upgrade one you want to keep on your character and progress with
 * Rune chest: Specific type of loot contener that drops 2-3 runes when opened
 * Rune merchant: Merchant specialized in runes that sells powerful runes for gold
 * Rune bag: Drops a random rune at the start of each new zone