Clean up GitHub Workflows (#3059)

* initial cleanup of github workflows

* only run pr-label workflow on push to master

* move docker ci/release summaries to scripts

* add XS label for PR's under 2 lines

* draft test job for Docker CI

* fix & activate Docker CI test job

* add debug step to docker CI

* fix Docker CI test container env

* Docker CI build matrix

* fixup build summaries

* fix pipes in summary

* optimize Dockerfile for layer caching

* more markdown escaping

* add gha cache scopes

* add Docker CI cache clean workflow

.github/workflows/scripts/docker-release-summary.sh

@@ -0,0 +1,85 @@
+#!/bin/bash
+meta=$(docker image inspect "$IMAGE_NAME" | jq '.[0]')
+
+EOF=$(dd if=/dev/urandom bs=15 count=1 status=none | base64)
+
+cat << $EOF
+# Docker Release Build summary 🚀🔨
+
+**Source:** $ref_type \`$current_ref\` -> [$repository@\`${commit_hash:0:7}\`]($source_url)
+
+**Image size:** $((`jq -r .Size <<< $meta` / 10**6))MB
+
+## Image details
+
+**Tags:**
+$(jq -r '.RepoTags | map("* `\(.)`") | join("\n")' <<< $meta)
+
+<details>
+<summary><h3>Layers</h3></summary>
+
+|    Age    |  Size  | Created by instruction |
+| --------- | ------ | ---------------------- |
+$(docker history --no-trunc --format "{{.CreatedSince}}\t{{.Size}}\t\`{{.CreatedBy}}\`\t{{.Comment}}" $IMAGE_NAME \
+    | grep 'buildkit.dockerfile' `# filter for layers created in this build process`\
+    | cut -f-3                   `# yeet Comment column`\
+    | sed 's/ ago//'             `# fix Layer age`\
+    | sed 's/ # buildkit//'      `# remove buildkit comment from instructions`\
+    | sed 's/\$/\\$/g'           `# escape variable and shell expansions`\
+    | sed 's/|/\\|/g'            `# escape pipes so they don't interfere with column separators`\
+    | column -t -s$'\t' -o' | '  `# align columns and add separator`\
+    | sed 's/^/| /; s/$/ |/'     `# add table row start and end pipes`)
+</details>
+
+<details>
+<summary><h3>ENV</h3></summary>
+
+| Variable | Value    |
+| -------- | -------- |
+$(jq -r \
+    '.Config.Env
+    | map(
+    split("=")
+    | "\(.[0]) | `\(.[1] | gsub("\\s+"; " "))`"
+    )
+    | map("| \(.) |")
+    | .[]' <<< $meta
+)
+</details>
+
+<details>
+<summary>Raw metadata</summary>
+
+\`\`\`JSON
+$meta
+\`\`\`
+</details>
+
+## Build details
+**Build trigger:** $event_name \`$current_ref\`
+
+| Parameter      | Value        |
+| -------------- | ------------ |
+| \`no_cache\`   | \`$inputs_no_cache\` |
+
+<details>
+<summary><code>github</code> context</summary>
+
+\`\`\`JSON
+$github_context_json
+\`\`\`
+</details>
+
+### Job environment
+
+#### \`vars\` context:
+\`\`\`JSON
+$vars_json
+\`\`\`
+
+#### \`env\` context:
+\`\`\`JSON
+$job_env_json
+\`\`\`
+
+$EOF