Remove panellists from panel information

[csarven]

Based on the observation that panel membership in the panels document is neither well-maintained or particularly meaningful or required by any process. People do hop-in-and-off the meetings or engaging in repositories or chat channels all the time. Anyone, including the W3C Solid Community Group participants as well as guests can participate by adhering to the Solid Code of Conduct. Guests do not have voting rights - if and when necessary. Membership in the CG is required for voting rights, in addition to agreeing to the CG Contributor License Agreement and the MIT License assigned to a work item or repository when making substantial contributions.

The essence of the above is reflected in the meeting template and the meeting guideline and announced in meetings when necessary, as well as the Solid process.

To simplify panel information, the proposal is to omit the panellists - it hasn't been demonstrably useful, and on the contrary it is shown to go stale and possibly misleading. All contributors to the panel can be known based on what's in public, e.g., through github, gitter, publications.