Document properties available for each template in serverless

[margalva]

Description of the modifications

In ADR serverless, on each template you can set its properties via attributes.
This simplifies a lot the API compared to the old, server version of ADR.
This request is to document / provide a way for a user to know the list of attributes available on each template type.
Ideally, for complex templates such as the Merge generator we'd like to provide an easy way to understand what each attribute is/does.

Useful links and references

No response