Add exports to all packages

[Feiyang1]

• Add esm builds for nodejs
• Add exports to all packages
• Defined esm entrypoints for Nodejs for all packages except for
  • @firebase/app/@firebase/app-compat to minimize dual package hazard
    
  • @firebase/messaging/@firebase/messaging-compat because one of its dependencies idb doesn't support esm in Nodejs.
    

Fixes #4846

[hsubox76]

I was a little confused about which builds need the emitModulePackageFile() plugin and which don't. Some seemed to be missing, but maybe there's a reason. I made a comment about how multiple instances of that plugin might be redundant if writing to the same directory but I don't think that applies to all "missing" plugin cases so maybe there's another reason they're not needed in those cases.

[benmccann]

this is great! thank you so much for this!

[kenkunz]

As a SvelteKit + Firebase developer, very happy to see this 👍. Thanks!