Option to prevent multiple h1 tags for basic openapi definition

[maxkrumpe]

Problem:
We use the ReactStandalone component in our next.js application and found the issue for multiple h1 tags in the rendered page.
For seo reasons it is bad to have multiple h1 tags in one page.

Solution
We would like to have a configuration option to only apply one h1 html tag as the title of the openapi definition but not for the underlying openapi tags.
The underlying openapi tags should have the h2 html tags.

We also tried to use the redocly cli instead and added a custom plugin with decorators but this did not work because we can only interact with the content but not the build html itself.