On-Demand Resources: Added functionality to apply prefetch categories to Addressables groups

[jwtan-unity]

Apple uses Prefetch Categories to define when On-Demand Resources (ODRs) are downloaded.

Main changes:

• You can now specify the prefetch category used by each Addressables group via the AppleODRSchema component.
• Each ODR now uses the name of the Addressables group as its tag (conforms with Apple's approach to grouping tags).
• Added post-process script that applies the specified prefetch category (and order) in the Xcode project.

The example Addressables groups in the project have also been modified to use different prefetch categories:

• Packs D, E, F: Initial Install Tags
• Packs G, H, I: Prefetched Tag Order
• Packs J, K, L: Download Only On Demand