[chore] docs update

[igorDykhta]

• update info about Vector Tile layer, Raster Tile layer and WMS layer

[Copilot]

Pull Request Overview

This PR updates documentation for layer types in Kepler.gl by standardizing image alt text formatting and adding new layer type documentation.

• Standardizes image alt text from double quotes to single quotes across all layer examples
• Adds missing documentation for Vector Tile layer and WMS layer with accompanying images
• Updates formatting and adds experimental labels for newer layer types

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