Need to run some checks before generating boilerplate files

[CodeSadhu]

Startify needs to first check whether the files and/or folders that it is about to generate already exist. If not, proceed with generation. If yes, pass these scenarios:

1. If folder exists (eg. utils), the files that are normally generated under the utils folder should be generated in the one that already exists
2. If the file exists (eg. utils/colors.dart), skip the creation of the file and display a message stating the skipped file name.