refactor: move ooni into the internal package (#168)

With this commit we've reorganised the package structure. Now I will
go more in depth and perform further refactoring.

internal/nettests/nettests.go

@@ -7,7 +7,7 @@ import (
 
 	"github.com/apex/log"
 	"github.com/fatih/color"
-	ooni "github.com/ooni/probe-cli"
+	"github.com/ooni/probe-cli/internal/ooni"
 	"github.com/ooni/probe-cli/internal/database"
 	"github.com/ooni/probe-cli/internal/output"
 	engine "github.com/ooni/probe-engine"

internal/nettests/nettests_test.go

@@ -5,7 +5,7 @@ import (
 	"path"
 	"testing"
 
-	ooni "github.com/ooni/probe-cli"
+	"github.com/ooni/probe-cli/internal/ooni"
 	"github.com/ooni/probe-cli/internal/database"
 	"github.com/ooni/probe-cli/internal/utils/shutil"
 )