TypeScript/JavaScript: support Bun runtime and package manager

[mfairley]

Is your feature request related to a problem? Please describe.
Bun https://bun.com/ is becoming a popular runtime alternative to Node. It'd be great if Pants had support for it.

Describe the solution you'd like
Support for both the Bun runtime and package manager

Additional context
It looks like Pants currently supports npm, pnpm and yarn. It'd be great to add Bun to that list.