OOB Asset Support

[Traviskn]

This adds support for out of band assets as requested in #236 and #271.

The example rive file and assets as well as most of the iOS implementation code are from this branch by @zplata https://github.com/rive-app/rive-react-native/tree/bump-ios-android-oob

A few quirks are:

• If using bundled assets, you must include the file extension on iOS, but must omit the file extension on Android.
• You must also your assets into the res/raw directory on Android.
• Font asset support is not yet complete on iOS

I would love feedback, I will see about adding font asset support to the iOS implementation as well

[Traviskn]

I've updated my branch with support for font assets on iOS. I've also updated the docs to explain the platform differences between asset names on iOS and Android. I've also updated the example to work cross platform

[HayesGordon]

Hi @Traviskn, this is great thanks for the contribution.

I have a local version of out of band assets support that expands on what Zach did in the above mentioned branch. It also allows for assets to be loaded in using require instead of updating Xcode/Android-Studio.

I'd need to clean up the initial draft and can tag you to review that - I'll aim for next week. Would love to get your, and others, input on which approach is best.

[Traviskn]

@HayesGordon that sounds great, I’ll look forward to seeing your PR! Passing in the asset reference via require sounds like a great api

[tslater]

@HayesGordon will your API be similar to the one for web? I finally found on discord a discussion of how to reload assets after the initial load by maintaining a reference to the asset object in the callback. I've tested here:
https://codesandbox.io/p/sandbox/out-of-band-react-typescript-re-load-8wqth3?file=%2Fsrc%2FApp.tsx%3A13%2C1&workspaceId=ws_NfoYyUpqSy5SuDSXnhT3eT

Ideally we could do the same in ReactNative?