[Feature]: Add the possibility to not generate main.html file

[neslinesli93]

What problem does this feature solve?

We are using server side rendering from a Elixir/Phoenix application, so index.html is generated at runtime and served by our Elixir backend. We could not find a way to skip generating main.html file in the output directory, it would be useful to have said option

What does the proposed API look like?

Don't know if this should be in output.html or something

[chenjiahan]

You can set tools.htmlPlugin to false:

https://rsbuild.dev/config/tools/html-plugin#disable-html