Add Traits and Specifications for common production workflows

[foundrytom]

This is inevitably incomplete and in need of future refinement, but we hope they are a good starting point

It serves to form a starting point to build real-world workflows to refine. We've already done many rounds on naming here, so unless anything is particularly egregious, or just incorrect, then let us not to get drawn into 🕳️ 🐇 s.

There are many things missing from this, but the goal is not to describe the world in its entirety. The requirement is to address specific workflows that are upcoming in the next 6 months, where we already a concrete need for a host and manager to both need a specific definition of data or entity characteristics.

Draft as still to come:

• ~Fine tooth comb checks on trait sets~ https://github.com/OpenAssetIO/OpenAssetIO-MediaCreation/pull/71/commits/9cf55c47a6845757dedb844ede0c0217e098752f
• ~Guidelines for adding new traits/specifications~

Commits are split by vague functional groupings to hopefully help reduce the WoT.

Closes OpenAssetIO/OpenAssetIO-MediaCreation#22

[foundrytom]

@elliotcmorris @feltech https://github.com/OpenAssetIO/OpenAssetIO-MediaCreation/pull/71/commits/9cf55c47a6845757dedb844ede0c0217e098752f seemed like a good idea?

[foundrytom]

@elliotcmorris @feltech Sundry updates:

• https://github.com/OpenAssetIO/OpenAssetIO-MediaCreation/pull/71/commits/f9872523063cf32572b11209fbd7b84ff9a0ab3c
• https://github.com/OpenAssetIO/OpenAssetIO-MediaCreation/pull/71/commits/07485443721bd3dc7da60d5fd6720b2612427e81
• https://github.com/OpenAssetIO/OpenAssetIO-MediaCreation/pull/71/commits/ada07ded439a396d28ad8708e6e3cdaaf352e87c

[foundrytom]

@elliotcmorris @feltech https://github.com/OpenAssetIO/OpenAssetIO-MediaCreation/pull/71/commits/f125b80de87ab67ccf3ed2ac7fc35f73d3dd5872 - aligning with USD