* 🐛 Bail out when no packages are found with default solvers
Checking packages is more tricky when a resolver is set. Resolvers
are capable of mutating the user request and remove part of the
constraints in order to resolve a specific solution.
This had the countereffect on a normal solver to not detect correctly
packages when missing from the wanted set and not proposed during
installation.
This should fix all the cases above taking into consideration of
resolvers and adding specific test-cases for it.
* ⚙️ Pin to tag for test image
It holds necessary state plus additional information relative to the
context which we are being run to (e.g. if we are in a terminal or not).
Besides in the future we can use it also as a contextual logger to
provide more smart logging capabilities.
This also replace the general global configuration instance that
previously was share between the core components.
