@kubb/core: add banner property to output

[nimo23]

What is the problem this feature would solve?

It would be nice to add the banner property to the @kubb/core output to define a default banner for all plugins that does not override the default banner. Example:

..
import type Oas from 'oas';

function getBanner(oas: Oas) {
return `/**
 * Generated from kubb.
 * Do not edit manually.
 * version: ${oas.api.info.version}
 */`
}

export default defineConfig(() => {
    return {
        name: 'my-openapi',
        ...
        output: {
        path: './src/api',
        clean: true,
        // define the default banner
        banner: (oas: Oas) => getDefaultBanner(oas)
        },
        plugins: [
            pluginOas({
                output: {
                    ...
                    // uses default banner
                }
            }),
            pluginTs({
                output: {
                    ...
                    // does not use the default banner, but the following custom one:
                    banner: () => `// my custom banner`
            },
            ..
}),

External documents/projects?

No response

What is the feature you are proposing to solve the problem?

With the default banner property, we don't have to repeat the banner property for each plugin, which makes the configuration cleaner (DRY = don't repeat yourself).

What alternatives have you considered?

No response