Improving UI/UX/DX in solid-panes and mashlib (aka the Solid data-browser)

@timbl and I are going to start work on improving the user interface, user experience and developer experience of solid-panes. With this issue I want to invite everyone to add their issues on the current design. We ask you to please add it as a comment here or create a new issue.

The hope with the work is to end up with a data browser that is intuitive and easy to use for end-users and flexible and easy to modify for developers.

I've added a new project to the Solid organization as this might span multiple repos (and actually multiple organizations, as mashlib in the linkeddata-organization will also probably be part of this work), and I invite you to follow the progress there. If you want to participate in the project I hope you contact me so that we can coordinate our efforts (you can of course contact Tim as well, but he's quite busy, so he might not respond). (But of course, as always, you can simply skip to submitting a PR if that's how you want to participate.)

No specific file, test, or entry point is named. Start by reviewing the Solid organization project and the current design in solid-panes, then inspect the related mashlib repository. A contribution would need a separately defined UI, UX, or developer-experience problem with agreed scope and completion criteria.