platform: add Akamai to the tested platforms

[tormath1]

In this PR we add Akamai to the Mantle tested platforms.

How to use

# set the token and get an image
AKAMAI_TOKEN=...
wget https://beta.release.flatcar-linux.net/amd64-usr/current/flatcar_production_akamai_image.bin.gz

# upload the image
AKAMAI_IMAGE_ID=$(./bin/ore akamai --akamai-token "${AKAMAI_TOKEN}" \
  create-image --file ./flatcar_production_akamai_image.bin.gz --name my-image
)
2024-12-03 10:18:32.495823 I | platform/api/akamai: Uploading image file: flatcar_production_akamai_image.bin.gz
2024-12-03 10:19:19.293890 I | platform/api/akamai: Image uploaded with ID: private/28753425 - waiting to be ready

# run the test
./bin/kola \
  --board=amd64-usr \
  --parallel 1 \
  --platform akamai \
  --akamai-token "${AKAMAI_TOKEN}" \
  --akamai-image "${AKAMAI_IMAGE_ID}" \
  --akamai-region "us-ord" \
  --akamai-type g6-standard-2
  run \
  --keys --key /home/tormath1/.ssh/id_rsa.pub \
  kubeadm.v1.31.0.flannel.base
=== RUN   kubeadm.v1.31.0.flannel.base
=== RUN   kubeadm.v1.31.0.flannel.base/node_readiness
=== RUN   kubeadm.v1.31.0.flannel.base/nginx_deployment
=== RUN   kubeadm.v1.31.0.flannel.base/NFS_deployment
--- PASS: kubeadm.v1.31.0.flannel.base (395.45s)
    --- PASS: kubeadm.v1.31.0.flannel.base/node_readiness (8.52s)
    --- PASS: kubeadm.v1.31.0.flannel.base/nginx_deployment (9.86s)
    --- PASS: kubeadm.v1.31.0.flannel.base/NFS_deployment (21.86s)
PASS, output in _kola_temp/akamai-2024-12-03-1100-78885

NOTE

The garbage collection is not yet fully functional: the filtering on the image does not work (it returns all the images), it has been raised on the Akamai side.