Provide more information about Exporting Charts

[HerbertsVaadin]

Solves:
#4768

Changes:

• Created new page Exporting to describe various export methods.
• Moved contents of "Exporting Charts as SVG" to the new page, as the "SVG Generator" tab
• Created a new tab "Remote Export Service" with content mostly from V8.
  • Added an image showing of the export menu.
  • Added links to set up export server and Highcharts export service
• Created a new tab "Offline module (unsupported)" that describes the state of this features support in Vaadin Charts.
  • Contains links to relevant GitHub issue and comment explaining how to implement it yourself.

[github-actions]

AI Language Review

• Exporting Charts as SVG

  • Ensure that the title consistently follows the title case: "Close the Generator" instead of "Close The Generator."
  • Ensure that the warning and note admonitions use standard formatting: [CAUTION] should have consistent capitalization.

• Usage with Lit

  • The order tag in the metadata is increased, likely indicating a change in content order. Ensure that this change reflects the intended navigation order in the documentation.

• Usage with React

  • The order tag in the metadata has been changed. Verify the change in section order aligns with the intended documentation hierarchy.

The structure and technical content seem consistent and well-organized.