bit import should save the component in package.json with relative path

[davidfirst]

in the project and not as an npm package. (e.g. @bit/is-string: ./components/is-string).

If a component was a dependency before and was saved in package.json as an npm package, change it to be a relative path in the project upon bit import.

This task should solve the following issue:
A user writes code that would be published as an npm package. In his local development environment, he imported a component using 'bit import' command and required it in his source code with the absolute syntax '@bit/component'. On his local, it works because of the symlink generated from ./components to node_modules/@bit. However, users who install his package, won't get this symlink, which results in a broken package.