report: select: add DM_REPORT_FIELD_TYPE_STRING_LIST to make a difference between STRING and STRING_LIST

The {pv,vg,lv,seg}_tags and lv_modules fields are reported as string
lists using the new dm_report_field_string_list - so we just pass
the list to the fn that takes care of reporting and item sorting itself.

lib/properties/prop_common.h

@@ -123,6 +123,7 @@ static int _ ## NAME ## _get (const void *obj, struct lvm_property_type *prop) \
 #define STR 1
 #define NUM 2
 #define SIZ 3
+#define STR_LIST 4
 
 #define FIELD_MODIFIABLE 0x00000001
 #define FIELD(type, strct, field_type, head, field, width, fn, id, desc, settable) \