Streamline load simulation efforts on Staging

Part of Simulate load on Staging (&7320 - closed) Emulation Goal:Stage#2.

Staging has few load tools to emulate traffic:

• traffic-generator loads static set of URLs
• cmbr - webcrawler that crawls through GitLab instance

Steps:

• Check with Infra and Quality teams if there are any other tools that are used - verified that there is no other tools running when traffic-generator was disabled
• Analyse current load simulation efforts
• Consolidate load testing efforts: - #351228 (comment 847006928)
  • Decide if Staging needs both traffic-generator and cmbr
  • Explore if traffic-generator can be improved and if GitLab Performance Tool could be helpful
• Bypass rate limit for gstg_load_generator to resolve 429 errors on crawling - https://gitlab.com/gitlab-com/gl-infra/chef-repo/-/merge_requests/1281, https://gitlab.com/gitlab-com/gl-infra/cmbr/-/issues/1

Decision

Use webcrawler cmbr as a single source of load simulation on Staging. See #351228 (comment 847006928)