Remove OpenPype and avalon references

[iLLiCiTiT]

Description

Make AYON and ayon naming as first class citizen for all functionality and metadata naming in repository.

Ideal goal is that openpype, pype and avalon are not mentioned anywhere in codebase. But that probably won't be possible because of backwards compatibility.

Codebase requirements

• Instances and containers do use AYON_INSTANCE_ID and AYON_CONTAINER_ID instead of AVALON_INSTANCE_ID and AVALON_CONTAINER_ID (constants from ayon-core).
• If there are metadata stored to scene, we're referring to them as "ayon" metadata and not "openpype", "pype" or "avalon".
• If there are metadata related to folder, it is not referred to it as "asset" (OpenPype term) - Use correct folder path or folder name based on functionality.
• If there are metadata related to product, it is not referred to it as "subset" (OpenPype term)
• If there are metadata related to product type, it is not referred to it as "family", except for publishing (OpenPype term)

And codebase need to change any of that, we must make sure it can be backwards compatible (read older scenes).

Create separate issues if it should be split to multiple PRs, and close the issue if all conditions are met.