feat: Rework workspace commands to be able to work with user namespace permissions only

[mmorhun]

Signed-off-by: Mykola Morhun mmorhun@redhat.com

What does this PR do?

All workspace commands are reworked in order to be able to work correctly if current user doesn't have permissions to read Che Server namespace. However, in such case we cannot automatically retrieve Che API URL, so it is required from user to provide it in --che-api-endpoint argument.
Also this PR moves all Che API related methods into a separate singleton class.

How to test

The following commands are supposed to be run manually one by one on a CRC cluster with a user which has no permissions for Che Server namespace.

Test commands

OS_TOKEN=$(oc whoami --show-token)
AT=$(curl -k -X POST -d "client_id=che-public" -d "subject_token=${OS_TOKEN}" -d "subject_issuer=openshift-v4" --data-urlencode "grant_type=urn:ietf:params:oauth:grant-type:token-exchange" --data-urlencode "subject_token_type=urn:ietf:params:oauth:token-type:access_token" https://keycloak-che.apps-crc.testing/auth/realms/che/protocol/openid-connect/token | jq -r .access_token)
ARGS="--access-token=$AT --che-api-endpoint=https://che-che.apps-crc.testing/api"

cat <<EOF >> devfile.yaml
metadata:
  generateName: wksp-custom-
apiVersion: 1.0.0
EOF

./chectl workspace:create $ARGS
./chectl workspace:list $ARGS
./chectl workspace:start $WID $ARGS
./chectl workspace:logs --workspace $WID --namespace=user-che
./chectl workspace:inject -k $ARGS
./chectl workspace:stop $WID $ARGS
./chectl workspace:delete $WID $ARGS

What issues does this PR fix or reference?

https://issues.redhat.com/browse/CRW-803

[AndrienkoAleksandr]

@mmorhun you have failed tests.

[mmorhun]

/retest

[flacatus]

/retest

[flacatus]

@mmorhun Openshift CI seems today is unstable. Ci centos jobs are removing so, should not work in this PR. Should be run tests in github actions: #851

[mmorhun]

Rebased

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: AndrienkoAleksandr, mmorhun, tolusha
To complete the pull request process, please assign
You can assign the PR to them by writing /assign in a comment when ready.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[mmorhun]

/retest