3D scan processor plugin API

[TheTrueCoder]

This issue will work on defining the API used to communicate between the webserver core and the photogrammetry processing backends. This will give the flexibility to add integrations with other programs in the future.

[TheTrueCoder]

Each plugin will need a class inside them with an init function that takes the path to the respective executable(s) and converts and stores them as absolute paths.

The first function I'll add to the API will take images and generate a model from them.
func generate_textured_mesh(image_folder: str, working_dir: str)