Select widget and align horitonzally or vertically

**What's your use case?**
On complex workflows, it's sometimes hard to follow visually the logic because widget boxes are not aligned.

**What's your proposed solution?**
The ability to align boxes, either horizontally, either vertically with the first selectiond widget box.


**Are there any alternative solutions?**
Not that I know

Start by locating the desktop canvas code that manages widget-box selection and positioning, then inspect how selected widgets are moved. Define the horizontal and vertical alignment behavior from the issue, including which selected box is the reference, and verify the result manually with a workflow containing several widgets.

Written by the indexing model from the issue text.