cli: add npm package

[fanatid]

Resolve #427

This pull request adds npm package for anchor-cli but only for linux/x64. This should good for CI and for most of developers.

Steps for publishing:

$ make build-anchor-cli
$ cd cli/npm-package && npm publish

Possible improvements:

1. Add js file as entrypoint which runs distributed binary in case of linux/x64 and global installed anchor otherwise (with version check).
2. Try to build wasm module (not sure, is it possible with the current wasi state or not).

[fanatid]

Thanks! Can you publish a package?

[armaniferrante]

Thanks! Can you publish a package?

Done!