Add rez packages generation for server_addons

[Minkiu]

This commit will add a python script that allows us to quickly generate packages for ayon-backend ingestion, either by copying them to the rez repo (not advised) or installing them via the ayon-frontend by uploading the resulting zips of the script.

Changelog Description

This is a PR that will allow us to then test the functionality of this ayon-backend PR: ynput/ayon-backend#29

Instead of creating a folder structure at this step, we delegate it to the rezbuild.py on the ayon-backend which expects the package.py and the usual folder structure of the addon source code (https://github.com/ynput/ayon-addon-template), thus this step is greatly simplified where we only copy the contents of the addon, add a package.py and zip them up. The caveat of the openpype package is the same, so an extra step to copy the required things of OpenPype into the client folder.

Testing notes:

1. Clone this branch
2. Run python create_ayon_rez_addons.py
3. Confirm zip archives have been generated in OpenPype/server_addon/rez_packages
4. If you are running the backend with the rez implementation: Install the addon, enable it and make sure it is able to initialize.

TODO

• Test all individual addons and change where required so they initialize in the backend

[iLLiCiTiT]

ZipFileLongPaths was used because shutil.make_archive did crash on Windows when a certain path length of path was used.

[iLLiCiTiT]

And there is missing manifest file which is used when package is uploaded via frontend.

[Minkiu]

ZipFileLongPaths was used because shutil.make_archive did crash on Windows when a certain path length of path was used.

Even with enabling longer than 260 char paths in Windows?

The manifest is no longer needed in this instance, the info is in the package.py this will only work with the rez backend.

[iLLiCiTiT]

Even with enabling longer than 260 char paths in Windows?

Well, you have to enable it, and you have to know that you have to enable it, most people don't. They'll just tell "it's broken" or "it does not work".

[mkolar]

No point merging this here at this point. Let's port to AYON please @Minkiu

[Minkiu]

These changes are now in this PR: ynput/ayon-core#64