feat: Display plugin settings in preferences/project preferences

[yurii-lunha-stansassets]

Develop a tool to display the plugin settings in unity preferences or project preferences.
Something like StansAssets.Plugins.Editor.PackageSettingsWindow but for preferences menus.

Example:
On the screen we have "Package Manager" plugin. Based on PackageSettingsWindow we have EditorWindow, and also we display our plugin settings in the Project/Preferences menu. We should develop a standard tool to display both ways.