[Feature]: Evolve specification and add JSON schema

[svrnm]

Problem Statement

The specification for the config files (https://github.com/cisco-open/app-simulator/tree/main/docs/specification) is still work in progress, it needs much more details and we need to revisit some of the attributes that APM game has, that we either want to take or remove.

I also think we should add a JSON schema (https://json-schema.org/) that allows verification of config files to follow the spec.

[svrnm]

Two more thoughts:

• We might want to introduce a top level version, which is 0 right now. If needed we can have major/minor as well, but overall the idea would be to bump the version to 1 (or greater) if we introduce breaking changes.
• We should normalize some attributes like imageNamePrefix, imageVersion, serviceAnnotation, etc. to image.namePrefix and image.version and k8s.annotations.service, etc.