[show/tests] Add support for "show isis summary" (no JSON support)

[isabelladeleon12]

Signed-off-by: [email protected]

What I did

How I did it

How to verify it

Previous command output (if the output of a command-line utility has changed)

New command output (if the output of a command-line utility has changed)

admin@vlab-01:~$ show isis summary
vrf             : default
Process Id      : 64
System Id       : 1720.1700.0002
Up time         : 01w5d02h ago
Number of areas : 1
Area 1:
  Net: 49.0001.1720.1700.0002.00
  TX counters per PDU type:
    P2P IIH: 367098
   LSP RXMT: 0
  RX counters per PDU type:
    P2P IIH: 119602
  Level-2:
    LSP0 regenerated: 3532
         LSPs purged: 0
    SPF:
      minimum interval  : 1
    IPv4 route computation:
      last run elapsed  : 00:00:29 ago
      last run duration : 1340 usec
      run count         : 3530
    IPv6 route computation:
      last run elapsed  : 00:00:29 ago
      last run duration : 215 usec
      run count         : 3530
admin@vlab-01:~$ 
admin@vlab-01:~$ show isis summary -h
Usage: show isis summary [OPTIONS]

  Show ISIS summary

Options:
  -h, -?, --help  Show this message and exit.
admin@vlab-01:~$