[DOCS]: Add "Cookie helper" page

[adiati98]

Description

We need to move the content from legacy repo and convert it to RST, as well as update the content.

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Important

Please read the below resources before contributing to help you with this task:

• Contributing guidelines
• Contributing to Mautic’s documentation
• Mautic technical writing style guide
• The "Suggestions (Optional)" section below for guides on how to update the page

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Relevant Documentation URL

https://devdocs.mautic.org/en/7.0/plugin_services/cookie_helper.html

Link to the content at legacy docs

https://github.com/mautic/developer-documentation/blob/main/source/includes/_plugin_services_cookie_helper.md

Are you willing to help us fix this by making a pull request?

No

Suggestions (Optional)

How to update the page

• Find the file that needs to be updated in the docs/ directory. The dev docs URL format is as such:

  https://devdocs.mautic.org/en/x.x/FOLDER_NAME/FILE_NAME.html
  

  For example, if the relevant URL is https://devdocs.mautic.org/en/7.0/plugin_extensions/manipulating_contacts.html, then find manipulating_contacts.rst file inside the plugin_extensions folder.

• Transfer the content under the note admonition. Look at other pages on how to structure the content.

• Review and update the content when you see fit.

• Follow the contributing guidelines that are listed in the "Resources" section above.

Screenshots or Screen Recordings (Optional)

No response