Add option to wget ISO on DUT. Refactor image-deploy.sh

Description

Make oem_autoinstall script to download ISO directly on DUT without storing on agent
Rename image-deploy.sh to provision-image.sh because it was adapted to TF provisioning stage and became quite different from the original. So to avoid confusion renaming it
Refactor provision-image.sh script to remove the old logic not relevant to TF provisioning

Documentation
- Updated docs and codeowners because image-deploy.sh was renamed
  Tests
  
  Success case: wget ISO to HP laptop and provision: https://testflinger.canonical.com/jobs/067ba38a-d929-407e-bda8-0237f5eaa48c
  1. SSH to DUT and verify file is downloaded in /home/ubuntu
  2. SSH to agent and verify no iso stored in /tmp/tesftlinger/run
  Fail case: Missing credentials for ISO download: https://testflinger.canonical.com/jobs/adf4cda9-6aba-47dd-bb1d-ee224bd42584