[EPIC] Review current E2E status

[salasberryfin]

Description

• Cleanup Makefile and Dockerfile #824
• Cleanup unused GitHub Workflows  #828 - some of them are not running and could be redundant:
  • E2E short: e2e-short, e2e-short-test
  • E2E long: e2e-long, e2e-long-test
• Validate if we can improve short E2E: using EIO runners, testing CAPRKE2 (some memory issues were detected), etc. #896
• We are using SPOT VMs for GCP runners (long tests), can this be a source of failed executions? Investigate if we should be moving to "standard" VMs.
• Runners not picking jobs up: some jobs are not being picked by runners intermittently. Can we identify why this is happening? We've experienced jobs waiting to be picked up and when other jobs are completed, runner would be removed and the waiting job will just time out https://github.com/rancher/turtles/actions/runs/11550471529/attempts/1
• E2E image sometimes get stuck when building #893
• Investigate if we can introduce more parallel E2E runs #898