chore(infra-chaos): Adding node-aff-perc & sequence in node-level chaos (#359)

Signed-off-by: shubhamchaudhary <shubham.chaudhary@mayadata.io>

charts/generic/node-io-stress/engine.yaml

@@ -32,5 +32,5 @@ spec:
               value: '10'
             
              ## enter the name of the desired node
-            - name: APP_NODE
+            - name: TARGET_NODE
               value: ''

charts/generic/node-io-stress/experiment.yaml

@@ -67,8 +67,8 @@ spec:
     - name: NUMBER_OF_WORKERS
       value: '4'    
 
-    ## enter the name of the desired node
-    - name: APP_NODE
+    ## enter the name of the target node
+    - name: TARGET_NODE
       value: ''    
 
     # Period to wait before and after injection of chaos in sec
@@ -83,6 +83,15 @@ spec:
     # provide lib image
     - name: LIB_IMAGE
       value: 'litmuschaos/go-runner:latest' 
+
+    ## percentage of total nodes to target
+    - name: NODES_AFFECTED_PERC
+      value: ''
+
+    ## it defines the sequence of chaos execution for multiple target nodes
+    ## supported values: serial, parallel
+    - name: SEQUENCE
+      value: 'parallel'
       
     labels:
       name: node-io-stress