functions/file_from_doc_dir library

1. image_cacheing package
2. documentation
3. functions/file_from_doc_dir.dart

image_cacheing package

1. Libraries
2. functions/custom_functions
3. functions/download_file
4. functions/file_from_doc_dir
5. functions/generate_file_name
6. image_cacheing
7. widget/image_cacheing_widget