compute_ctl: start pg in cgroup for vms (#4920)

Starts `postgres` in cgroup directly from `compute_ctl` instead of from
`vm-builder`. This is required because the `vm-monitor` cannot be in the
cgroup it is managing. Otherwise, it itself would be frozen when
freezing the cgroup.

Requires https://github.com/neondatabase/cloud/pull/6331, which adds the
`AUTOSCALING` environment variable letting `compute_ctl` know to start
`postgres` in the cgroup.

Requires https://github.com/neondatabase/autoscaling/pull/468, which
prevents `vm-builder` from starting the monitor and putting postgres in
a cgroup. This will require a `VM_BUILDER_VERSION` bump.

.github/workflows/build_and_test.yml

@@ -752,7 +752,7 @@ jobs:
       run:
         shell: sh -eu {0}
     env:
-      VM_BUILDER_VERSION: v0.16.3
+      VM_BUILDER_VERSION: v0.17.5
 
     steps:
       - name: Checkout
@@ -775,6 +775,7 @@ jobs:
         run: |
           ./vm-builder \
             -enable-file-cache \
+            -cgroup-uid=postgres \
             -src=369495373322.dkr.ecr.eu-central-1.amazonaws.com/compute-node-${{ matrix.version }}:${{needs.tag.outputs.build-tag}} \
             -dst=369495373322.dkr.ecr.eu-central-1.amazonaws.com/vm-compute-node-${{ matrix.version }}:${{needs.tag.outputs.build-tag}}