migrate package manager from npm to pnpm

[mellodev]

npm package manager works, but is incredibly slow compared to modern replacements. There are several popular alternatives, including Yarn and pnpm, which offer huge performance increases and developer quality of life improvements. Based on my experience with other projects, pnpm is a better choice vs yarn. The migration is incredibly simple and reversible at any time (the only change is the lockfile). Here is a comparison: https://www.geeksforgeeks.org/pnpm-vs-npm/