CI: Document the 'all-in-one' layout + small refactoring (#10725)

* Rename aio to all-in-one and document it

ADTM.
Acronyms don't tell much.

* Refactor vm_count in tests provisioning

.gitlab-ci/packet.yml

@@ -31,8 +31,8 @@ packet_cleanup_old:
     - make cleanup-packet
   after_script: []
 
-# The ubuntu20-calico-aio jobs are meant as early stages to prevent running the full CI if something is horribly broken
-packet_ubuntu20-calico-aio:
+# The ubuntu20-calico-all-in-one jobs are meant as early stages to prevent running the full CI if something is horribly broken
+packet_ubuntu20-calico-all-in-one:
   stage: deploy-part1
   extends: .packet_pr
   when: on_success
@@ -41,22 +41,22 @@ packet_ubuntu20-calico-aio:
 
 # ### PR JOBS PART2
 
-packet_ubuntu20-aio-docker:
+packet_ubuntu20-all-in-one-docker:
   stage: deploy-part2
   extends: .packet_pr
   when: on_success
 
-packet_ubuntu20-calico-aio-hardening:
+packet_ubuntu20-calico-all-in-one-hardening:
   stage: deploy-part2
   extends: .packet_pr
   when: on_success
 
-packet_ubuntu22-aio-docker:
+packet_ubuntu22-all-in-one-docker:
   stage: deploy-part2
   extends: .packet_pr
   when: on_success
 
-packet_ubuntu22-calico-aio:
+packet_ubuntu22-calico-all-in-one:
   stage: deploy-part2
   extends: .packet_pr
   when: on_success
@@ -235,7 +235,7 @@ packet_fedora37-calico-swap-selinux:
   extends: .packet_pr
   when: manual
 
-packet_amazon-linux-2-aio:
+packet_amazon-linux-2-all-in-one:
   stage: deploy-part2
   extends: .packet_pr
   when: manual