Fix/add imports crash

[arthurgeron]

• Fixed crash when there is a import declaration but no specifiers;
• Fixed crash/misbehavior when adding specifiers on import statements with only the default export (e.g. import React from 'react') during autofix;
• Now properly ignores react type import statements;
• Moved method from common file to fix circular dependency;
• Renamed common to src/utils/index to keep file names consistent;
• Removed unused vars and other minor fixes.