Tests and validation configuration in the manifest file

[pathumego]

fontpackage.toml can store specific tests, checks and other configurations related to QA and validation tools such as Fontbakery. What would that look like? And we might have to develop this standard separately so it can be independently versioned dpending on Fontbakery roadmap and features

cc @graphicore

[graphicore]

Fontbakery has no configuration files at the moment, so I don't know how that would look like.