added model_api for use with UI

Created by: Amaan1234567

Added model_api.cpp which holds the model_api class, this class has two main functions one for normal generation and one for generation with image the class also has checks builtin to start ollama if it isnt running and also to pull the model if the model isnt available on device.

usage: instantiate the model_api class with the name of the model(should match the name on the ollama website , can do custom ollama ones, but that functionality i will add later), then call the generation_with_image function with prompt from user and the path to the image or screenshot and it will return the response back as a std::string.