[Lens page] Remove duplications and add links to chart types

[alaudazzi]

=== NOT READY FOR REVIEW ===

This PR reworks the Lens page to remove duplicated content and add links to the first new set of chart types: Area, Line, Bar, Metric and Table charts.

Fixes #4262

Generative AI disclosure

1. Did you use a generative AI (GenAI) tool to assist in creating this contribution?

• Yes
• No

[github-actions]

Vale Linting Results

Summary: 1 suggestion found

💡 Suggestions (1)

File	Line	Rule	Message
explore-analyze/visualize/lens.md	14	Elastic.WordChoice	Consider using 'efficiently' instead of 'simply', unless the term is in the UI.

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[github-actions]

🔍 Preview links for changed docs

• explore-analyze/visualize/charts/metric-charts.md
• explore-analyze/visualize/charts/tables.md
• explore-analyze/visualize/lens.md

[alaudazzi]

The same example (Compare differences over time) is documented in Line chart (Compare current versus previous period with time shift). I wonder if it makes sense to keep it in Lens as well. I redirected it to Line.

[alaudazzi]

Considerations about the section Assign colors to terms:

1/ Depending on the chart type, the configuration options vary. The way it is currently documented in the section Configure color mapping in a chart, is quite confusing.

2/ I suggest we keep high-level recommendations like
- Color options and accessibility
- Best practices

and defer the specific settings to each single chart page.

[alaudazzi]

Considerations about the section Create partition charts with multiple metrics:

It's floating in the middle of nowhere, adding little value to the overall page. I would remove it, and I'm not sure if it has redirect to another page.