Introduce package spec format version example format_version: '1.0'

Per discussed during one of our team weekly, we will upgrade the package spec version as It is almost impossible to add control over package spec.

Most of the time it breaks a lot of packages and will imply bulk changes a the same time.

Changes packages spec will help us be more strict on validation for new incoming packages, leave older packages as is, add new types and fields without impacting packages without format_version.

Related:
#313
#338
#281