more validation is needed for "system host-device-label" related cli

[Difu Hu]

Brief Description
-----------------
"system host-device-label" related cli needs more validation to handle error cases

Severity
--------
Minor

Steps to Reproduce
------------------
case1: add same label with different values, only the last value gets added. "system host-device-label-assign controller-1 0000:b2:00.0 label3=1 label3=2 label3=3", only label3=3 is added.
case2: When there are label1=abc and label1=dddddddd for same device, "system host-device-label-remove controller-1 pci_0000_b2_00_0 label1" only removes the first one.
case3: add/remove label with special label/value (eg. label!1 label!a), get following output.
      3.1 label!1 two labels "labelip" and "addr" added with "None" value, and prompt “system host-device-label-remove controller-1 0000:b2:00.0 labelip addr | grep 128.224.150.247”
      3.2 labelx = 1 three labes "labex", "" and "1" added with "None" value
      3.3 remove “label!a” prompt error with “system host-device-label-remove controller-1 0000:b2:00.0 labelansible-playbook lab-install-playbook.yaml -e "@local-install-overrides.yaml"”
case4: add/remove label with special (incorrect) PCI device (eg. 0000;b2:00.0 0000!b2:00.0), prompt “-sh: !b2: event not found”

Reproducibility
---------------
permanent

System Configuration
--------------------
Lab-name: wp_16_17

Branch/Pull Time/Commit
-----------------------
Designer build from 2020-06-09_20-00-00

Last Pass
---------
N/A

Test Activity
-------------
Functional Testing

[Ghada Khalil (gkhalil)]

stx.5.0 - minor usability issues

[Teresa Ho (teresaho)]

Fixed in the commit https://opendev.org/starlingx/config/commit/4a210f212e9ac8a4439b0fe312beeb545ee1b1fd
Reviewed in https://review.opendev.org/#/c/741970/

[Difu Hu (difuhu)]

Verified on 2020-09-13_20-00-00.