[Test] Dev Spaces load tests based on kubect apply

[SkorikSergey]

What does this PR do?

Currently, for load tests we use UI e2e approach - https://github.com/eclipse/che/tree/main/tests/e2e/specs

This is not the best way to do the load testing. Need to reconsider this approach and use
kubectl apply which would run simultaneously hundreds of workspaces. We should time:

• number of failures
• startup time (avg / median)

Screenshot/screencast of this PR

What issues does this PR fix or reference?

https://issues.redhat.com/browse/CRW-5633

How to test this PR?

1. Log in to Openshift cluster with DevSpaces deployed from terminal
2. Start load-test.sh script from test/e2e/performance/load-tests. Set number of started workspaces by -c parameter(like./load-test.sh -c 5).
3. This script gets cpp sample devfile.yaml from DevSpaces devfile registry and starts workspaces.
4. As results there are average time of workspace starting and number of failed workspaces.

Test logs

[user@fedora load-tests]$ ./load-test.sh -c 15
Context "user-devspaces/api-ocp413-crw-qe-com:6443/user" modified.
Clean up the environment
Download the devfile
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  3811  100  3811    0     0   9274      0 --:--:-- --:--:-- --:--:--  9295
Start workspaces from sample devfile
2502
1309
devworkspacetemplate.workspace.devfile.io/che-code-cpp created
devworkspace.workspace.devfile.io/dw1 created
devworkspace.workspace.devfile.io/dw2 created
devworkspace.workspace.devfile.io/dw3 created
devworkspace.workspace.devfile.io/dw4 created
devworkspace.workspace.devfile.io/dw5 created
devworkspace.workspace.devfile.io/dw6 created
devworkspace.workspace.devfile.io/dw7 created
devworkspace.workspace.devfile.io/dw8 created
devworkspace.workspace.devfile.io/dw9 created
devworkspace.workspace.devfile.io/dw10 created
devworkspace.workspace.devfile.io/dw11 created
devworkspace.workspace.devfile.io/dw12 created
devworkspace.workspace.devfile.io/dw13 created
devworkspace.workspace.devfile.io/dw14 created
devworkspace.workspace.devfile.io/dw15 created
Wait for all workspaces are started and calculate average workspaces starting time
devworkspace.workspace.devfile.io/dw1 condition met
Devworkspace dw1 starting time: 13 seconds
devworkspace.workspace.devfile.io/dw2 condition met
Devworkspace dw2 starting time: 23 seconds
error: timed out waiting for the condition on devworkspaces/dw3
Timeout waiting for dw3 to become ready or an error occurred.
Error from server (NotFound): pods "workspace447d6cf327464a20" not found
error: timed out waiting for the condition on devworkspaces/dw4
Timeout waiting for dw4 to become ready or an error occurred.
Error from server (NotFound): pods "workspace30636f3ff61144ff" not found
devworkspace.workspace.devfile.io/dw5 condition met
Devworkspace dw5 starting time: 21 seconds
error: timed out waiting for the condition on devworkspaces/dw6
Timeout waiting for dw6 to become ready or an error occurred.
Error from server (NotFound): pods "workspace60b59ef1d3584e05" not found
devworkspace.workspace.devfile.io/dw7 condition met
Devworkspace dw7 starting time: 18 seconds
devworkspace.workspace.devfile.io/dw8 condition met
Devworkspace dw8 starting time: 16 seconds
devworkspace.workspace.devfile.io/dw9 condition met
Devworkspace dw9 starting time: 26 seconds
devworkspace.workspace.devfile.io/dw10 condition met
Devworkspace dw10 starting time: 13 seconds
devworkspace.workspace.devfile.io/dw11 condition met
Devworkspace dw11 starting time: 12 seconds
devworkspace.workspace.devfile.io/dw12 condition met
Devworkspace dw12 starting time: 11 seconds
devworkspace.workspace.devfile.io/dw13 condition met
Devworkspace dw13 starting time: 11 seconds
devworkspace.workspace.devfile.io/dw14 condition met
Devworkspace dw14 starting time: 10 seconds
devworkspace.workspace.devfile.io/dw15 condition met
Devworkspace dw15 starting time: 9 seconds
==================== Test results ====================
Average workspace starting time for 12 workspaces from 15 started: 15 seconds
3 workspaces failed. See logs for details.

PR Checklist

As the author of this Pull Request I made sure that:

• The Eclipse Contributor Agreement is valid
• Code produced is complete
• Code builds without errors
• Tests are covering the bugfix or new feature
• The repository devfile is up to date and works
• Sections What issues does this PR fix or reference and How to test this PR completed
• Relevant user documentation updated
• Relevant contributing documentation updated
• CI/CD changes implemented, documented and communicated

Reviewers

Reviewers, please comment how you tested the PR when approving it.