refactor generator & template

[phatpham9]

Todo:

• remove unnecessary /generators/app/templates/src/package-name dir
• remove README.md & .gitignore as existed in https://github.com/boringcodes/repo-template repo
• ask more questions for passing user inputs to package.json file such as: homepage, bugs, repository urls, etc...
• fix the problem of not copying .huskyrc file
• install dependencies using yarn instead of npm & bower by default
• update README.md's usage instruction