refactor(cmd): standardize subcommand aliases with kubectl shortnames

[doronkg]

What this PR does / why we need it?

This PR refactors subcommand aliases to match kubectl official shortnames, as disaplyed in kubectl api-resources.
Fixes:

• Remove excess singular aliases (i.e. "job", "replicaset")
• Remove unofficial shortnames (i.e. "scrt")
• Support uncovered shortnames (i.e. "crds")

In addition, this PR refactors the Usage section in README.md to address kor's subcommands in singular form.

PR Checklist

• This PR adds new code
• This PR adds docs

GitHub Issue

[XX-XX]

Notes for your reviewers

Kor Original Aliases

$ grep -r Aliases cmd/kor/ -B 1
cmd/kor/clusterroles.go-        Use:     "clusterrole",
cmd/kor/clusterroles.go:        Aliases: []string{"clusterroles"},
--
cmd/kor/configmaps.go-  Use:     "configmap",
cmd/kor/configmaps.go:  Aliases: []string{"cm", "configmaps"},
--
cmd/kor/crds.go-        Use:     "customresourcedefinition",
cmd/kor/crds.go:        Aliases: []string{"crd", "customresourcedefinitions"},
--
cmd/kor/daemonsets.go-  Use:     "daemonset",
cmd/kor/daemonsets.go:  Aliases: []string{"ds", "daemonsets"},
--
cmd/kor/deployments.go- Use:     "deployment",
cmd/kor/deployments.go: Aliases: []string{"deploy", "deployments"},
--
cmd/kor/finalizers.go-  Use:     "finalizer",
cmd/kor/finalizers.go:  Aliases: []string{"fin", "finalizers"},
--
cmd/kor/hpas.go-        Use:     "horizontalpodautoscaler",
cmd/kor/hpas.go:        Aliases: []string{"hpa", "horizontalpodautoscalers"},
--
cmd/kor/ingresses.go-   Use:     "ingress",
cmd/kor/ingresses.go:   Aliases: []string{"ing", "ingresses"},
--
cmd/kor/jobs.go-        Use:     "job",
cmd/kor/jobs.go:        Aliases: []string{"job", "jobs"},
--
cmd/kor/pdbs.go-        Use:     "poddisruptionbudget",
cmd/kor/pdbs.go:        Aliases: []string{"pdb", "poddisruptionbudgets"},
--
cmd/kor/pods.go-        Use:     "pod",
cmd/kor/pods.go:        Aliases: []string{"po", "pods"},
--
cmd/kor/pv.go-  Use:     "persistentvolume",
cmd/kor/pv.go:  Aliases: []string{"pv", "persistentvolumes"},
--
cmd/kor/pvc.go- Use:     "persistentvolumeclaim",
cmd/kor/pvc.go: Aliases: []string{"pvc", "persistentvolumeclaims"},
--
cmd/kor/replicasets.go- Use:     "replicaset",
cmd/kor/replicasets.go: Aliases: []string{"rs", "replicaset", "replicasets"},
--
cmd/kor/roles.go-       Use:     "role",
cmd/kor/roles.go:       Aliases: []string{"roles"},
--
cmd/kor/secrets.go-     Use:     "secret",
cmd/kor/secrets.go:     Aliases: []string{"scrt", "secrets"},
--
cmd/kor/serviceaccounts.go-     Use:     "serviceaccount",
cmd/kor/serviceaccounts.go:     Aliases: []string{"sa", "serviceaccounts"},
--
cmd/kor/services.go-    Use:     "service",
cmd/kor/services.go:    Aliases: []string{"svc", "services"},
--
cmd/kor/statefulsets.go-        Use:     "statefulset",
cmd/kor/statefulsets.go:        Aliases: []string{"sts", "statefulsets"},
--
cmd/kor/storageclasses.go-      Use:     "storageclass",
cmd/kor/storageclasses.go:      Aliases: []string{"sc", "storageclassses"},

Kubectl Official Shortnames

$ kubectl api-resources | awk '{print $1, $2}' | egrep -v '/|v1' | column -t
NAME                        SHORTNAMES
componentstatuses           cs
configmaps                  cm
endpoints                   ep
events                      ev
limitranges                 limits
namespaces                  ns
nodes                       no
persistentvolumeclaims      pvc
persistentvolumes           pv
pods                        po
replicationcontrollers      rc
resourcequotas              quota
serviceaccounts             sa
services                    svc
customresourcedefinitions   crd,crds
daemonsets                  ds
deployments                 deploy
replicasets                 rs
statefulsets                sts
horizontalpodautoscalers    hpa
cronjobs                    cj
certificatesigningrequests  csr
events                      ev
ingresses                   ing
networkpolicies             netpol
poddisruptionbudgets        pdb
priorityclasses             pc
storageclasses              sc

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 40.92%. Comparing base (2fdeab2) to head (1348c48).
Report is 2 commits behind head on main.

Files	Patch %	Lines
pkg/kor/multi.go	0.00%	2 Missing ⚠️
pkg/kor/all.go	0.00%	1 Missing ⚠️

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Additional details and impacted files

@@           Coverage Diff           @@
##             main     #300   +/-   ##
=======================================
  Coverage   40.92%   40.92%           
=======================================
  Files          58       58           
  Lines        2913     2913           
=======================================
  Hits         1192     1192           
  Misses       1532     1532           
  Partials      189      189           

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[yonahd]

Nice cleanup