Replace PNG documentation images with SVG for virtual switch types

[dirkjanfaber]

Replace the 10 PNG images in `resources/docs/` with SVG versions exported from Figma.

Tasks

• Export SVG versions from Figma
• Place SVG files in `resources/docs/`
• Update references in `src/nodes/victron-virtual-functions.js`
• Remove old PNG files

Benefits

• Smaller file size (~221KB → ~30KB)
• Scalable graphics that stay sharp at any zoom level"