The VoIP module was reorganized and cleaned up to align with newer coding practices used elsewhere in Odoo. This should make future VoIP improvements easier and safer to deliver, with little expected change for end users.

Pursue the refactoring of the VoIP module:
- Remove unnecessary newlines in xml attributes
- Rename widget css classes as follows: o_widget_WidgetName_templatePart

Part of task 2376357

The VoIP module’s internal files have been reorganized into clearer widget-based sections, and older code structure has been updated to modern module standards. This does not introduce a new user-facing feature, but it should make future improvements and maintenance easier and more reliable.

Start refactoring the VoIP module by reorganizing files:
- Move files from /js/ and /xml/ to newly created /widgets/ subdirectories
- Split systray_voip_menu.xml from dialing_panel.xml
- Replace old odoo modules with ES modules

Part of task 2376357