Feature/add references

[IkeikeP]

Hey as discussed, here are the proposed changes to add references to collections.
Essentially it is now possible to convert all items in a collection to references. These references are stored inside Addressables.

It is then possible to add references or items to the collection by using the add (plus) button:

For the sake of simplicity, I'll provide examples using the names of the Weapons collection shown in the screenshots.
The conversion process entails several steps:

• Marks every ScriptableObjectCollectionItem of the collection as Addressable. An Addressable group is created (or reused) for this scenario.
• Creates new item base class type (WeaponBase).
• Creates a new reference class type (WeaponReference) as inherits the new item base class (WeaponBase).
  • This reference class contains a reference object that only contains a GUID to the target item.
• Swaps the the base class (ScriptableObjectCollectionItem) of the item class ( WeaponBase) for the new base class ( WeaponBase). This step does not fully regenerate the class, it just finds and replaces the base class type.
• Updates the collection class (WeaponCollection) swapping the type argument of the generic collection class (previously Weapon) for the new base class (WeaponBase).
  • This also does not fully regenerate the class. (if the developers wrote code in the collection class it won't be overridden)
• Creates scriptable object items of the reference class. These SOs are created in a new directory named "References" next to the Item collection directory.
• Regenerates the static class code.
  Once the process is complete, developers can use the Load util method provided for each item on the static class (example LoadAK47()) to load the item.

Some advantages of the reference system:

[+]Unified solution that can be applied to any collection the same way
[+]The only thing getting into the resources are GUIDs
[+]Automatically sets the required assets as addressables in a isolated group
[+]More control, can partially load/unload collections

Additionally, this PR includes fixes to the core system that I've stumbled upon testing the references feature.

Keep in mind this is the first iteration and more improvements are possible in the horizon. (For example, better editor UI to manipulate references in the collection)

Also as you asked, I've updated the wiki. But this update is only in my fork (Not possible to create a PR to the wiki repo nor I have permissions to push commits to it)

[brunomikoski]

Awesome! I will get the branch and do some local tests with it, but overall looks really good!

[brunomikoski]

Some questions and small code code format issues

[IkeikeP]

Thank you for the review, glad you liked it!
All the comments have been addressed. I have also made some minor improvements and fixes which were mostly code styling related.