Tracking issue for usable alpha

[notgull]

Right now, the current app consists of a handful of disparate parts. This issue aims to provide a way for future work to be organized in such a way that we can have a usable alpha of this program in the near future.

End Goal

Before we move forward I would like to have the following in place:

• A decently stable web frontend with an accurately node display and the ability to communicate with the backend. You will be able to import images, run them through a node processor, and receive a new image as output.
• A GIMP plugin that uses a similar format to communicate with a similar backend that is spawned on the local machine.
• A backend that receives data from both frontends and uses that to process images.
• Supporting libraries for all of the above.

Web Frontend Tasks

• Reorganize the code to fit Vue in a much more idiomatic way (cc @meredith-grace)
• Communicate with the backend server to process nodes. (Drive web frontend using ontario #53, Fix ontario webbugs #58)

GIMP Frontend Tasks

• Implement additional CI/CD for plugin development
• Implement plugin development environment support for linux (Implement plugin development environment support for linux #36)
• Solidify plugin entry point and plugin application loop (Solidify plugin entry point and plugin application loop #37)
• Implement a node-based interface using gtknodes or otherwise (Implement a node system for the GIMP frontend #24).
• Add image pipelining capabilities. (Ontario gtknode #60)

Backend Tasks

• Translate all images to a single processing format (maybe AVIF? Might not be supported in all browsers. Maybe match on it?) (Convert images to webp on arrival to backend #34)
• Implement at least one image operation (probably compositing?) (Fix ontario webbugs #58)
• Rewrite backend in Python (Rewrite backend with Python/GEGL #47)

Supporting Libs Tasks

• Add output node to libnode serialization format (libnode and libnodepy) (Add output node to the node pipeline serialization format #28)
• Potentially port libnode to C++ to support C++ porting effort. We're not moving in this direction anymore.
• Expose final output node format in serialized libnode format (Add output node to the node pipeline serialization format #28).
• Implement total node unlinking for nodes.

Misc Tasks

• Configure the CI system to test more of the program's surface.

Incomplete list, I'll add more as I think of them.

[notgull]

With #60 and @meredith-grace's unmerged commits, we've reached our goal here. Good job, everyone!