Move "multipathconfread" into common repository

"multipathconfread" actor is compatible with RHEL 8 so let's move
it into common repository. For the moment it will not be of any use but
will help us to fix issue with enabling multipath as we refactored some
parts of related functionality there.

repos/system_upgrade/el7toel8/actors/multipathconfread/libraries/multipathconfread.py → repos/system_upgrade/common/actors/multipathconfread/libraries/multipathconfread.py

@@ -3,15 +3,15 @@
 
 from leapp.libraries.common import multipathutil
 from leapp.libraries.common.rpms import has_package
+from leapp.libraries.stdlib import api
 from leapp.models import (
     CopyFile,
     InstalledRedHatSignedRPM,
     MultipathConfFacts,
     MultipathConfig,
     MultipathConfigOption,
-    TargetUserSpaceUpgradeTasks,
+    TargetUserSpaceUpgradeTasks
 )
-from leapp.libraries.stdlib import api
 
 
 def _change_existing_option(curr_options, opt_name, opt_value):

repos/system_upgrade/el7toel8/models/multipathconffacts.py → repos/system_upgrade/common/models/multipathconffacts.py

@@ -1,4 +1,4 @@
-from leapp.models import Model, fields
+from leapp.models import fields, Model
 from leapp.topics import SystemInfoTopic