fix npm install script

[rouzwelt]

Motivation

fixes issue with installing the js package from npm, that required some unused dependencies from rainix

Solution

fix the package.json prepublish hook to skip trying to build if the package is already built and packed (installing from npm) and to try build when the package is not already built (installing from git), this is done through a ./scripts/build.js script which gets run on prepublish hook and checks if ./dist directory exists or not.

Checks

By submitting this for review, I'm confirming I've done the following:

• [x] made this PR as small as possible
• [ ] unit-tested any new functionality
• [ ] linked any relevant issues or PRs