feat: new library Data Flow Diagram Basics

[excalibot]

For Making complete data flow diagrams. This library includes common symbols and notations for data flow diagrams created by Yourdon & Coad, Yourdon & DeMarco, and Gane & Sarson.

Main symbols and their other common names

• Process: Function, Transformation, etc
• Data Store: File, Database, Warehouse, etc
• External Entity: Terminator, Outside system, etc

Submitted by @predatorx7

Items: Data Store, User, External Entity, Process, Data Store (GS), Entity, Interface, Process with Location (GS), Process (GS)

Installation link