Document new Injectors

[davidjgonzalez]

@niekraaijmakers

The injectors need to clarify how they work

• Add example Sling Model code
• Add example JCR Node structure (as makes sense)
• Add example injected value (ex. in Example comments or something)

https://adobe-consulting-services.github.io/acs-aem-commons/features/sling-model-injectors/index.html

[davidjgonzalez]

@niekraaijmakers not sure if you ever go time to document these. we've had a few requests for these docs to get completed. If there is adequate info/clear samples somewhere i can take a stab.