Dashboard: add text

[laurasootes]

Add some more text to make the use of the dashboard and the examples a bit clearer. Specifically:

• Landing page: rename “pages”, and clarify what images/text/timeseries means in this context
• Landing page: what is the dashboard
• Page titles: make page titles more informative than simple “Image explanation"
• Examples: explain what the example is: what is the data, what is the task, what do the colours mean Image classification page:
• Image classification
• Tabular classification
• Tabular regression
• Text classification
• Time series classification weather
• Time series classification FRB

Suggestion from Sarah to remove the pages section fully

[elboyran]

Adding this comment in the first seemingly relevant still open issue I found:

• fix typos and reformulate a bit.
  

• edit to avoid repetitions
  

[elboyran]

For the colors of the attribution maps, borrow/get inspired by this nice explanation.

[elboyran]

Landing page implemented:

[elboyran]

Image page and example:

[elboyran]

Tabular page and examples:

[elboyran]

Text page and examples:

[elboyran]

Time series page and examples:

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