wip: improve fixer, add always peer config option

[noahnu]

Example config from an internal monorepo:

module.exports = {
    excludeFiles: ["**/lib/**", "**/docs/**"],
    devFiles: ["**/*.test.{js,jsx,ts,tsx}"],
    alwaysPeerDependencies: [
        'react',
        'react-dom',
        'prop-types',
        'axios',
        'immutable',
        'styled-components',
        'react-redux',
        'redux-saga',
        'react-redux',
    ],
}

and run with: yarn ghost-imports-buster --skipRoot --fix.