Open source asset manager

[jmccarten-wetafx]

Currently RMTC supports only a filesystem based asset manager running against 'file' URI schemes.

Integrating a common asset manager such as OpenAssetIO to defer URI transformation and publish would complete the core abstractions and unlock further adoption.

[jmccarten-wetafx]

At present the asset manager has a few responsibilities:

• Resolving to and from concrete URIs - say from an asset manager ID to a disk URI
• Executing artifact conversions via pipelines
• Publishing assets to the asset manager
• Watermarking assets with provenance information - e.g. meta data embeddings into images

Given it's not clear what asset management system we would directly support - the existing Filesystem Asset Manager implementation covers most of the above without a requirement for an additional dependency. It might be sufficient until we decide on a shared asset manager suitable for core.