Entity hub: Small refactor and add product & version

[iLLiCiTiT]

Changelog Description

Refactored BaseEntity a little to support all common attributes so they don't have to be reimplemented in each entity. Also added basic support for product and version.

Additional info

Modified arguments in EntityHub methods and in base classes to make a little bit more sense. That might be backwards incomaptible a little, but as EntityHub is used by services at the first place, it should be ok for them to update code with update of ayon api.

Only remainders are that folder and task types are kept as first argument in add_new_ methods -> those would couse most damage.

Entity hud changes:

• In some cases parent_id was renamed to be more specific (e.g. folder_id in case of task entity).

TODOs future PRs

• Add more helper functions to get product and versions (e.g. by name/version and parent it).
• Add products as children of folder and versions as children of product.

Testing notes:

1. First of all existing functionality should work as before - all syncs (ftrack, shotgrid, editorial) should work.
2. It is possible to create and update products and versions.

[iLLiCiTiT]

If there is too much changes I can split the PR to refactor and adding new entity types.

[kalisp]

Seems to be working (tested on full SG sync to AYON).