Port various systems/patterns from 2ship

[garrettjoecox]

This back-ports various systems/patterns from my findings on 2ship.

• CustomItem - At the sacrifice of appending a single ITEM/GI at the end of the vanilla enums, this allows us to have fully customizable item give sequences, allowing you to draw whatever you want (or nothing), display a cutscene or not, and call any arbitrary code (or none) when the item is "granted". This will result in us removing a lot of touch points throughout the vanilla source that we have made over the years to handle various cases of item gives and ice traps.
• ShouldActorSpawn & OnOpenText - self explanatory new hooks
• New CustomMessage patterns - Admittedly this isn't as simple as it is on 2ship because I had to adapt to our already existing CustomMessage concept, but the patterns still all apply. Allows you to on-the-fly replace or create a new message and display it without having to go through the message table mechanism.

None of these new systems are actually used anywhere yet, this PR simply introduces them, I will have a follow up migrating the Randomizer & Vanilla item give queues to use these.

Build Artifacts

• soh-windows.zip
• soh-linux.zip
• soh-mac.zip

[Pepper0ni]

While I can't comment on a lot of hook stuff, I did see an issue in the custom message handling.

[garrettjoecox]

Updated, some stuff was removed as it was already ported in the newly merged #5101

still nothing functionally changing in this PR so it can go in whenever, the functional changes come in #6019

[Malkierian]

Small conflict in CustomMessageManager cropped up, then I think this can go in.