[docs:gsoc26] Documentation for MassCommand feature

[dee077]

This issue is created to track documentation for issues

1. [feature:gsoc26] Add MassCommand asynchronous execution pipeline for batch device commands #1344
2. [feature:gsoc26] Add Django admin workflow for mass command execution and real-time monitoring #1345
3. [feature:gsoc26] Admin action to execute mass commands from the device list page #1347
4. [feature:gsoc26] Link Command execution history to MassCommand history and execution tracking #1348
5. [feature:gsoc26] Add REST API for mass command execution and operation management #1349

and add static media files (such as images or GIFs) to the docs branch after the complete implementation of each feature, to visually document the final workflow and functionality.