[Feature]: Support multiple environment configuration

[9aoy]

What problem does this feature solve?

Enhance the current multi-target building capabilities, users can define completely different Rsbuild configurations for different environments.

Different environments can be different usage scenarios of the same rsbuild target (node ​​SSR / node RSC) or different rsbuild targets (web / node SSR)

before:

after:

What does the proposed API look like?

The design of environment configuration in Rsbuild is inspired by Vite Environment API. Thanks to the Vite team ❤️

Add the environments field in Rsbuild config, and environment configuration can override the basic Rsbuild configuration.

export default {
  // Shared configuration for all environments
  source: {
    alias: {
      '@common': './src/common',
    },
  },
  environments: {
    // configuration for web
    web: {
      source: {
        entry: {
          index: './src/index.client.js',
        }
      },
      target: 'web',
      tools: {
        bundlerChain: (chain) => {
           chain.plugin('xxx').use(xxx);
        }
      },
    },
    // configuration for ssr
    'ssr': {
      source: {
        entry: {
          index: './src/index.server.js',
        }
      },
       target: 'node',
       tools: {
          htmlPlugin: false,
       }
    },
  },
};

MVP

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1. feat: Add basic environment config #2623
   +0
   
2. feat: Support get environment info via rsbuld api #2632
   +0
   
3. chore: Generate rspack config based on environment instead of output.targets
4. breaking change: Replace output.targets with output.target
5. breaking change: Replace api.context.targets / entry / distPath / xxx with api.environments[index].xxx
6. feat: Should use environment.config instead of api.getNormalizedConfig() in plugins
7. feat: api.getHTMLPaths support get specify environment htmlPath by environment parameter
8. breaking change: output.emitAssets changed to boolean type
9. breaking change: output.overrideBrowserslist no longer supports object type

More

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1. feat: support add single environment plugin via environments.[name].plugins configuration.
2. feat: inspect config support output environment config
3. feat: supports building only specified environment through --environment=xxx in rsbuild cli.
4. feat: rsbuild server supports rsbuild.environments.xxx api
5. breaking change: Deprecated service-worker target
6. breaking change: output.distPath.server / worker no longer support
7. breaking change: Deprecated target / isServer / isWebWorker util in configuration function