Define context for scoped operation across core types

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.

pkg/compiler/compiler_suite_test.go

@@ -18,14 +18,11 @@ package compiler_test
 import (
 	"testing"
 
-	. "github.com/mudler/luet/cmd/util"
-
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
 )
 
 func TestSolver(t *testing.T) {
 	RegisterFailHandler(Fail)
-	LoadConfig()
 	RunSpecs(t, "Compiler Suite")
 }