Easier Gizmo Menu settings

[MustafaJafar]

Changelog Description

resolve #46

• Enhance settings
• Enhance loading logic here.

Note

Settings in this PR should be backward compatible. i.e. it shouldn't break copy settings.
If it's not please report.

Demo

Settings:

• Mode 1: Add a Gizmo Directory Path
  
• Mode 2: Add Gizmos By definitions
  

Testing notes:

1. Try different Gizmo Menu options
2. When launching Nuke, Gizmo should be added as configured in the settings.

[MustafaJafar]

Loading logic enhancement boils down to
But, I didn't add to the PR. (I didn't test adding a source dir. I only tested adding gizmos by list)

import nuke 
import platform

from ayon_core.pipeline import get_current_project_name
from ayon_core.settings import get_current_project_settings
from ayon_core.resources import get_ayon_icon_filepath
from ayon_nuke.api.gizmo_menu import GizmoMenu

# load configuration of custom menu
project_name = get_current_project_name()
project_settings = get_current_project_settings()
platform_name = platform.system().lower()


for gizmo_settings in project_settings["nuke"]["gizmo"]:
    # Get the toolbar.
    toolbar_name = gizmo_settings["toolbar_menu_name"]
    toolbar_icon_path = gizmo_settings.get(
        "toolbar_icon_path", {}).get(platform_name)

    # Create the toolbar
    toolbar_menu = GizmoMenu(
            title=toolbar_name,
            icon=toolbar_icon_path or get_ayon_icon_filepath()
        )

    # Add gizmos based on options
    option = gizmo_settings["options"]
    if option == "gizmo_source_dir":
        gizmo_paths_to_add = gizmo_settings[option]
        toolbar_menu.add_gizmo_path(gizmo_paths_to_add)
    elif option == "gizmo_definition":
        toolbar_menu.build_from_configuration(gizmo_settings["gizmo_definition"])