Update Dash documentation

[94rain]

• Update the deployment instructions for Dash application and remove the Dockerfile
• Add the webpage title of the Dash application: "Population by country - Ploomber Cloud Dash Application".

Closes https://github.com/ploomber/cloud-backend/issues/694

pending dash deployment to prod

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📚 Documentation preview 📚: https://ploomber-doc--128.org.readthedocs.build/en/128/

[edublancas]

@neelasha23 please review

[neelasha23]

I think we need to remove the Dockerfile from the clinical-analytics folder as well? @94rain

[94rain]

I think we need to remove the Dockerfile from the clinical-analytics folder as well? @94rain

Good point, removed dockerfile from clinical-analytics example

[edublancas]

cool, @94rain let us know when the this is deployed so we can merge this!