[Test] Update load-tests script

[SkorikSergey]

What does this PR do?

Update load-tests script:

• use local devworkspace.yaml file for ws starting
• add trap command to start cleanup if script failed or interrupted
• split script to separate function
• save logs to logs folder

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 uses local dewvorspace.yaml to start workspaces.
4. As results there are average time of workspace starting and number of failed workspaces.

Test logs

[sskoryk@fedora load-tests]$ ./load-test.sh -c 50 -t 240
Parameter -c was set to  50 .
Parameter -t was set to 240 second.
Clean up the environment
devworkspace.workspace.devfile.io/dw31 created
devworkspace.workspace.devfile.io/dw15 created
devworkspace.workspace.devfile.io/dw33 created
devworkspace.workspace.devfile.io/dw30 created
devworkspace.workspace.devfile.io/dw8 created
devworkspace.workspace.devfile.io/dw48 created
-||-
devworkspace.workspace.devfile.io/dw2 created
devworkspace.workspace.devfile.io/dw1 created
Wait for all workspaces are started
devworkspace.workspace.devfile.io/dw30 condition met
devworkspace.workspace.devfile.io/dw33 condition met
devworkspace.workspace.devfile.io/dw15 condition met
-||-
devworkspace.workspace.devfile.io/dw2 condition met
devworkspace.workspace.devfile.io/dw47 condition met
devworkspace.workspace.devfile.io/dw21 condition met
devworkspace.workspace.devfile.io/dw4 condition met
Calculate average workspaces starting time
Devworkspace dw1 starting time: 28 seconds
Devworkspace dw2 starting time: 32 seconds
Devworkspace dw3 starting time: 30 seconds
-||-
Devworkspace dw44 starting time: 29 seconds
Devworkspace dw49 starting time: 33 seconds
Devworkspace dw50 starting time: 26 seconds
==================== Test results ====================
Average workspace starting time for 50 workspaces from 50 started: 25 seconds
0 workspaces failed. See failed workspace pod logs in the current folder for details.
Clean up the environment

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.

[SkorikSergey]

Next steps for load-tests script:

- fix the script for mac os
- make sure that it is possible to run the script from che workspace on workspaces.openshift.com against another cluster e.g. dogfooding with 100 workspaces (-c 1000)
- replace devworkspace with devfile
add argument that would allow to specify devfile that will be used for the load tests instead of default (could be URL or located on disk)