[Feature]: support compilation.runtimeTemplate api

[hardfist]

What problem does this feature solve?

lots of plugins use runtimeTemplate api to inject runtime code(like https://www.npmjs.com/package/webpack-retry-chunk-load-plugin) ,without runtimeTemplate api it is hard to migrate webpack plugin to be compatible with rspack.

notice runtimeTemplate and mainTemplate are two different things, runtimeTemplate is more like a utility function and mainTemplate is more like a builtin custom runtime module

What does the proposed API of configuration look like?

same as webpack https://github.com/webpack/webpack/blob/main/lib/RuntimeTemplate.js