Added starter files for assignment 4

Assignment-04/fork-exec-1.png

Assignment-04/fork-exec-2.png

Assignment-04/questions.md

Assignment-04/readme.md

Assignment-04/starter/.debug/launch.json

Assignment-04/starter/.debug/tasks.json

Assignment-04/starter/bats/assignment_tests.sh

Assignment-04/starter/bats/student_tests.sh

Assignment-04/starter/dragon.c

Assignment-04/starter/dsh_cli.c

Assignment-04/starter/dshlib.c

Assignment-04/starter/dshlib.h

Assignment-04/starter/gitignore.txt

Assignment-04/starter/makefile

Assignment-04/starter/shell_roadmap.md