Schemas: Slightly simplify mode regexp

Slightly simplify "mode" attribute regexp in schemas for "config_files"
and "changed_managed_files" scopes.
Schemas: Fix indentation

Fix indentation in schemas for "config_files" and
"changed_managed_files" scopes.
Schemas: Improve definition names

Change definition names in schemas for "config_files" and
"changed_managed_files" scopes. The new names better describe what the
definitions represent.
Merge pull request #180 from SUSE/schema-config-files-changed-managed-files-tweaks

[Review] Request from 'dmajda' @ 'SUSE/machinery/schema-config-files-changed-managed-files-tweaks'