InlineAssetReader

## What problem does this solve or what need does it fill?

An inline asset reader is one in which the data for the asset is encoded entirely within the asset path. It's similar in concept to a "data url".

The motivation is to allow runtime computed objects, such as materials, to be created on the fly and managed like assets with strong handles.

See discord thread [here](https://discord.com/channels/691052431525675048/749332104487108618/1219358538925740093).

## What solution would you like?

The `InlineAssetReader` is an asset reader that doesn't actually read anything: it just returns a zero-length byte array. It is intended to be used in conjunction with an asset loader that decodes the asset path and constructs an asset based on the information in the decoded path.

## What alternative(s) have you considered?

I considered instead having a `Base64AssetReader` that actually looks at the path and decodes it into a byte array, but doing this in the asset loader gives more flexibility.

No files or tests are named. Start by locating the asset reader and asset loader APIs, then review how asset paths are passed between them. Done means an inline reader returns a zero-length byte array while a loader can decode the asset path and construct the requested runtime asset.

Written by the indexing model from the issue text.