Formatting issues on changelogs

[btat]

The changelog files (e.g. https://github.com/rancher/turtles-product-docs/blob/main/versions/v0.19/modules/en/pages/changelogs/changelogs/v0.18.0.adoc) contain a number of formatting issues, which are listed below. The script used to generate the changelog files should be updated to fix these.

• Incorrect header levels. The first header starts at level 2, which means there's no page title (the page's HTML <title> renders as untitled and affects SEO).
• The date is formatted as a header when it shouldn't be.
• Unneeded quotation marks around the version number and date. The quotation marks are rendered on the page and table of contents on the right.
• The first 3 lines repeat the same information and should be refactored.