Optimize and enhance Dragonfly dragonfly-injector (Webhook)

[gaius-qi]

Description

Refactor and optimize the functionality and code of Dragonfly dragonfly-injector.

Task

1. Refactor and optimize the functionality and code.
2. Integrate into Dragonfly's Helm Chart.
3. Add documentation.

Link

Injector Repo: https://github.com/dragonflyoss/dragonfly-injector
Helm Chart: https://github.com/dragonflyoss/helm-charts
Website: https://github.com/dragonflyoss/d7y.io