WebComponentPane update

[mgarin]

WebComponentPane has some styling issues in dark theme ( #532 #534 #536 ) and also has some potential issues with being blocked by hover state ( #531 ) - this needs to be fixed.

Also a complete "face lift" might be nice for the component as it's been written centuries ago and uses some of the outdated styling approaches.

Drop location should also be displayed as the drag operation goes on ( #549 ) so it is more obvious where the element will be dropped when mouse is released.

[mgarin]

There are some complications I've encountered with this component, so I'll be moving it to v1.2.12 update as it might take some time and I don't want to delay the release any further.

[mgarin]

Still working on this in background, but some important changes and fixes will be done to the library first (planned in upcoming v1.3.0 version). WebLaF versioning is also getting adjusted to appropriately reflect changes made in different updates and to allow me to push important fixes outside of larger updates.