Move files related to building compute image into compute/ dir

Seems nice to keep all these together. This also provides a nice place
for a README file to describe the compute image build process. For
now, it briefly describes the contents of the directory, but can be
expanded.

.github/workflows/build_and_test.yml

@@ -651,7 +651,7 @@ jobs:
           provenance: false
           push: true
           pull: true
-          file: Dockerfile.compute-node
+          file: compute/Dockerfile.compute-node
           cache-from: type=registry,ref=cache.neon.build/compute-node-${{ matrix.version }}:cache-${{ matrix.arch }}
           cache-to: ${{ github.ref_name == 'main' && format('type=registry,ref=cache.neon.build/compute-node-{0}:cache-{1},mode=max', matrix.version, matrix.arch) || '' }}
           tags: |
@@ -670,7 +670,7 @@ jobs:
           provenance: false
           push: true
           pull: true
-          file: Dockerfile.compute-node
+          file: compute/Dockerfile.compute-node
           target: neon-pg-ext-test
           cache-from: type=registry,ref=cache.neon.build/neon-test-extensions-${{ matrix.version }}:cache-${{ matrix.arch }}
           cache-to: ${{ github.ref_name == 'main' && format('type=registry,ref=cache.neon.build/neon-test-extensions-{0}:cache-{1},mode=max', matrix.version, matrix.arch) || '' }}
@@ -691,7 +691,7 @@ jobs:
           provenance: false
           push: true
           pull: true
-          file: Dockerfile.compute-node
+          file: compute/Dockerfile.compute-node
           tags: |
             neondatabase/compute-tools:${{ needs.tag.outputs.build-tag }}-${{ matrix.arch }}
 
@@ -779,7 +779,7 @@ jobs:
       - name: Build vm image
         run: |
           ./vm-builder \
-            -spec=vm-image-spec.yaml \
+            -spec=compute/vm-image-spec.yaml \
             -src=neondatabase/compute-node-${{ matrix.version }}:${{ needs.tag.outputs.build-tag }} \
             -dst=neondatabase/vm-compute-node-${{ matrix.version }}:${{ needs.tag.outputs.build-tag }}
 

.github/workflows/trigger-e2e-tests.yml

@@ -107,7 +107,7 @@ jobs:
           if [ "$GITHUB_EVENT_NAME" == "pull_request" ]; then
             for f in $(gh api "/repos/${GITHUB_REPOSITORY}/pulls/${PR_NUMBER}/files" --paginate --jq '.[].filename'); do
               case "$f" in
-                vendor/*|pgxn/*|libs/vm_monitor/*|Dockerfile.compute-node)
+                vendor/*|pgxn/*|libs/vm_monitor/*|compute/Dockerfile.compute-node)
                   platforms=$(echo "${platforms}" | jq --compact-output '. += ["k8s-neonvm"] | unique')
                   ;;
                 *)