Transition to Nordic Semiconductor's extension

This release disables the extension if Nordic Semiconductor's extension is present.
In the future, this extension will be deprecated in favor of Nordic's official extension, and all new features will be implemented in that extension instead.

• Disable extension functionality if Nordic Semiconductor's extension is installed
• Update icon to fix new Zephyr documentation style
• Fix expansion of environment variables in configuration
• Support new Kconfig.module format
• Support kconfig-ext in west modules
• Highlight expression operators