Add custom GUI support and deploy from API

[cxnt]

Update Supervisely SDK version to v6.73.50
Add quick start for Serving YOLOv8
Add GitHub action for building and pushing docker image
Add methods:

• init_gui() - User defined GUI for model selection. Returns widget
• update_gui() - enable/disable user GUI if model is served/stopped
• set_params_to_ui() - method to set GUI from API
• get_params_from_ui() - get selected params from GUI to use in load_model()
• download_weights() - helper func to download checkpoint (can be removed)
• load_model_meta() - load project_meta from model
• load_model() - main method to deploy model

Add models.py with updated sctructure for models