Refactor NDM code

[kmova]

There are several aspects of the code that can be refactored as listed below:

• Move some of the code from /cmd folder into parent folder and keep the /cmd only for launching the service by pulling in different packages together. Examples:
  • Move Probe logic from cmd/ndm-daemonset to /probes.
  • Move Filter logic from cmd/ndm-daemonset to /filter.
• Move environment variables handling to a separate package
• add more verbose logs to all types of filters, with info on why a device was included or excluded.
• Refact all the unused label constants and make use of standard label prefixes from client package.
• Refactor os disk filter code, so that multiple disks are not added in the exclude path
  If the user has given the following disk config:

  /dev/sda1 -- /boot
  /dev/sda1 -- /
  

  And the user has exclude points /,/boot. The filterpath will have /dev/sda twice in the exclude path which is unnecessary. This code part need to be modified.