feat: add context switching in TestStep

[kumar-mallikarjuna]

What this PR does / why we need it:

Fixes #558

Testing
Files

.
├── e2e
│   └── case
│       ├── 00-teststep.yaml
│       └── ns.yaml
├── kubeconfig
└── kuttl-test.yaml

# 00-teststep.yaml

apiVersion: kuttl.dev/v1beta1
kind: TestStep
apply:
- ns.yaml
kubeconfig: ~/.kube/config
context: kind-data-plane-aws

# ns.yaml

apiVersion: v1
kind: Namespace
metadata:
  name: test-ns

# kuttl-test.yaml

apiVersion: kuttl.dev/v1beta1
kind: TestSuite
testDirs:
- ./e2e
timeout: 2400
startControlPlane: false

Contexts

k config get-contexts
CURRENT   NAME                    CLUSTER                 AUTHINFO                NAMESPACE
          cluster                 cluster                 user
          kind-data-plane-aws     kind-data-plane-aws     kind-data-plane-aws
          kind-data-plane-aws-2   kind-data-plane-aws-2   kind-data-plane-aws-2
*         kind-data-plane-gcp     kind-data-plane-gcp     kind-data-plane-gcp

Namespace Created in the specified (non-default) context

$ k --context kind-data-plane-aws get ns -w
NAME                 STATUS   AGE
default              Active   20h
kube-node-lease      Active   20h
kube-public          Active   20h
kube-system          Active   20h
local-path-storage   Active   20h
pd-hcomp-1           Active   20h
kuttl-test-pleasant-duckling   Active   0s
test-ns                        Active   0s
test-ns                        Terminating   0s
kuttl-test-pleasant-duckling   Terminating   0s
test-ns                        Terminating   5s
kuttl-test-pleasant-duckling   Terminating   5s
test-ns                        Terminating   5s
kuttl-test-pleasant-duckling   Terminating   5s

[porridge]

Thanks, this looks nice!
Can you please add this new setting to docs/? And also see a nitpick inline.

[kumar-mallikarjuna]

Hi @porridge , thanks for the review. I've incorporated the comments. Could you please take a look?

[porridge]

😍