Improve build system and support ESM

[winston0410]

Right now medusa is only supporting CJS module, and used babel as the compile/build tool. This setup is 4~5 years older than the modern system, and as Vite and ESM is becoming mainstream now, I think it will be great to modernize the build tool

Two limitations with the current setup:

• cannot use medusa develop in a monorepo that installs packages globally(e.g Nx), as it is using a Babel with a hardcoded path
• cannot use ESM package without hack like fix-esm

[Bernix01]

I would like to add that npm packages started to drop CJS support rendering them incompatible with medusa.

[ghardin1314]

Our company is very on the fence about using Medusa and this could be a big deal breaker. Seems like the underlying tech setup is ~5-8 years behind in terms of bundling, etc. Would like to hear more from the devs on their plans forward with this

[carstenblt]

The longer this is unresolved, the more it will become a problem