Diskmanage: extract nvme wearout from smartctl text

extract the info from the line:
Percentage Used: XX%

also adapt the tests

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

test/disk_tests/nvme_smart/disklist_expected.json

@@ -1,6 +1,6 @@
 {
     "nvme0n1" : {
-	"wearout" : "N/A",
+	"wearout" : 100,
 	"vendor" : "unknown",
 	"size" : 512000,
 	"health" : "PASSED",

test/disk_tests/nvme_smart/nvme0n1_smart_expected.json

@@ -1,5 +1,6 @@
 {
     "text" : "\nSMART/Health Information (NVMe Log 0x02, NSID 0xffffffff)\nCritical Warning:                   0x00\nTemperature:                        32 Celsius\nAvailable Spare:                    100%\nAvailable Spare Threshold:          10%\nPercentage Used:                    0%\nData Units Read:                    1,299,288 [665 GB]\nData Units Written:                 5,592,478 [2.86 TB]\nHost Read Commands:                 30,360,807\nHost Write Commands:                470,356,196\nController Busy Time:               12\nPower Cycles:                       98\nPower On Hours:                     687\nUnsafe Shutdowns:                   21\nMedia and Data Integrity Errors:    0\nError Information Log Entries:      0\n",
     "health" : "PASSED",
-    "type" : "text"
+    "type" : "text",
+    "wearout": 100
 }