fix disk failure step 1 - happy path, fix by cloning template node

for each node with failed disks, it will be fixed with step 1 powerOff node, step 2:
createReplacementVm, step 3: a chef bootstrap step on the bad node.

Changes include:
1. implement clusterHealService to fix cluster errors, start from disk failure
2. implement disk failure handling job and according steps
3. record system disk in table disk. It's a plus besides the data and swap disk
4. update CreateVmSp to attach existed vmdks, only create and add disks that don't
  have vmdk path