Validation package metadata

[kMutagene]

we need to add frontmatter to validation packages to ensure certain things are known to other tools (e.g. arc-validate).

Currently, this is what I found so far:

• file name of the badge, must be unique across all packages
• file name of the junit file, must be unique across all packages

this also means that this repo needs a test suite to ensure uniqueness, also for file names.