First feedback about the v6.0.0

[herve-lg]

I allow myself a first feedback after one day of using version 6.0.0rc1:

The +:

• The general design even more modern and more integrable in different GUI:
  - the big banner "Welcome to Apache Superset" from the homepage is removed (more neutral page)
  - The choice to switch to a dark or light interface (theme)
• The integration of OSM in the deck.gl charts (more aligned with the phylosophy of the Apache2.0 license), which allows for dispensing with Mapbox tiling
• The mention of Mapbox disappears from the view when selecting OSM (Did we switch to MapLibre?)
• The addition of plugins via a much more intuitive interface.
• The addition of the Gantt chart
• The problem that occurs when switching from one language to another in 5.0.0 is fixed. There are no more residues of the other language in the "Settings for example".
• ...

Really, greetings to the entire user community and all those who contributed to it.

The -:

• Absence of a legend in the deck.gl cards;
• We can no longer modify the color of the borders of polygonal entities in deck.gl..;
• APP_ICON does not work at my place.
• I have a lot of errors in generating thumbnails
• ...