ITA-1209 : Add status flag to filter pods by the current status.phase

[phariharan-wish-zz]

Ctl: Add -a/--a flag for getting pods
The get pods retrieves all pods of all statuses - Pending, Running, Succeeded, Failed, Unknown.

Since the get pods command already retrieves all pods, this ticket addresses a status flag that allows user to filter the pods by the current Status.Phase

-s, --status string Filter pods by specified status

Example:

➜  ctl git:(add_a_flag) ✗ ./main get pods -s Failed                                                
CONTEXT                 NAMESPACE      NAME                                                  READY  STATUS  RESTARTS  AGE         K8S_ENV  AZ
app-01-prod.k8s.local   kron           example-2-1591161485-jzlxd                            0/1    Failed  0         132h8m19s   prod     us-west-1a
app-01-prod.k8s.local   kron           example-2-1591161485-pjhjd                            0/1    Failed  0         132h8m26s   prod     us-west-1a
app-01-prod.k8s.local   merchant-cron  v3-oauth-api-daily-usage-report-1590645600-8666n      0/2    Failed  0         275h26m24s  prod     us-west-1a
app-01-prod.k8s.local   wish-cron      backup-route53-dns-to-s3-1590771707-lrgsb             0/2    Failed  0         240h24m44s  prod     us-west-1a
app-01-prod.k8s.local   wish-cron      bbsolr-query-payload-1591211321-m2dkk                 0/2    Failed  0         118h17m50s  prod     us-west-1a
app-03-stage.k8s.local  infra-cron     test-1590620590-t7kb7                                 0/1    Failed  0         282h23m21s  stage    us-west-1a
app-03-stage.k8s.local  infra-cron     test-1590620590-w9g4g                                 0/1    Failed  0         282h23m14s  stage    us-west-1a
app-03-stage.k8s.local  infra-cron     test-1590634420-nl8lx                                 0/1    Failed  0         278h32m51s  stage    us-west-1a
app-03-stage.k8s.local  infra-cron     test-1590634420-pgzzx                                 0/1    Failed  0         278h32m45s  stage    us-west-1a
app-03-stage.k8s.local  kron           test-example-1591220130-ppwzl                         0/1    Failed  0         115h50m55s  stage    us-west-1a
app-03-stage.k8s.local  kron           test-example-1591220130-zxtn5                         0/1    Failed  0         115h51m1s   stage    us-west-1a
app-03-stage.k8s.local  merchant-cron  test-merchant-1590667840-hx2wn                        0/2    Failed  0         269h15m51s  stage    us-west-1a
app-03-stage.k8s.local  merchant-cron  test-merchant-1590667943-q7crk                        0/2    Failed  0         269h14m8s   stage    us-west-1a
app-03-stage.k8s.local  merchant-cron  test-merchant-1590670638-ngfxs                        0/2    Failed  0         268h29m13s  stage    us-west-1a
app-03-stage.k8s.local  wish-cron      weekly-load-onesource-tax-treatment-1591574400-bck8n  0/2    Failed  0         17h26m27s   stage    us-west-1a
app-05-dev.k8s.local    linkerd        linkerd-heartbeat-1589912280-g7xfs                    0/1    Failed  0         479h2m56s   dev      us-west-1a
app-05-dev.k8s.local    linkerd        linkerd-heartbeat-1589912280-hl6vf                    0/1    Failed  0         478h57m15s  dev      us-west-1a

[codecov]

Codecov Report

Merging #35 into master will increase coverage by 0.14%.
The diff coverage is 57.14%.

@@            Coverage Diff             @@
##           master      #35      +/-   ##
==========================================
+ Coverage   33.92%   34.07%   +0.14%     
==========================================
  Files          52       52              
  Lines        2022     2031       +9     
==========================================
+ Hits          686      692       +6     
- Misses       1309     1311       +2     
- Partials       27       28       +1     

Impacted Files	Coverage Δ
cmd/get.go	0.00% <0.00%> (ø)
pkg/client/logpods.go	0.00% <0.00%> (ø)
cmd/util/parsing/options.go	82.50% <75.00%> (-2.35%)	⬇️
cmd/describe.go	32.03% <100.00%> (+0.66%)	⬆️
pkg/client/listpods.go	71.92% <100.00%> (ø)

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