Add connections for layers with the same attributes

[liujvnes]

Currently, multiple graphics cannot have their attributes edited

It is recommended to add connections for layers with the same attributes

1. Add a connection icon to the layer panel (blue part)
2. Multiple selected graphics can create a connection
3. For multiple connected graphics, parts with the same attributes can have their attributes edited
4. Multiple attribute editing (e.g., if connected graphics have two of the same colors, both colors are displayed in Properties - Fill)
5. Clicking on one graphic can select multiple connected graphics, and expanding the identifying arrow allows for quick attribute selection
6. Double-clicking a graphic selects only that single graphic for individual editing
7. Connections can be set in the layer panel#2871 (red part)
8. Add links to filtered layers. Once a layer is linked, subsequent layers with the same identifier will automatically be linked. These filtered layers will be automatically connected as set in Layer Panel Feature Enhancements #2871 (e.g., filter red layers and add a connection, subsequent layers identified as red will automatically create a link). This is very convenient when there are too many layers.