Feat/stackitsdk 517 service deletion

[cgoetz-inovex]

Introduce go build tool to generate and read plans.

Use go build tool to create service deletion PRs.

Review Instructions

• the first commit creates the build tool to generate plan files, this should be reviewed throughly
• most other commits refactor the existing build to use the tool
• commit feat(ci): create PRs for deleted branches, unify plan location creates PRs for deleted services and contains new code
• commit feat(ci): sdk-create-pr does not push/create PR when NO_PUSH is set adds a NO_PUSH option to create-pr for easier local testing

Testing Instructions

Testing refactorings:

• checkout this branch locally
• the following script creates a new temp dir of the sdk-generator, checks out the last commit on main and runs the generator for all 3 langauges, then it checks out the latest commit of this branch and builds all 3 languages. This leaves you with a temp directory with 6 generated SDKs.
• diff the SDKs to confirm the build refactoring did no changes, e.g.: diffoscope --no-default-limits --markdown diff-python.md --max-diff-block-lines 10000 --max-report-size 0 --exclude "**/.git" --exclude-command "stat.*" --exclude "**/.venv" --exclude "**/.gradle" base-python-sdk branch-python-sdk/

Testing service deletion:

• checkout this branch and run make download-oas and make generate-go-sdk
• run NO_PUSH=1 scripts/sdk-create-pr.sh foo bar
• check the service deletions in stdout (lbapplication, iaasalpha etc.)

Testscript:

#!/usr/bin/env bash
# Generate every SDK at the branch base on main and at the branch tip. The
# retained directories can be compared with diff.
set -euo pipefail

BRANCH_REF=${1:-HEAD}
MAIN_REF=${2:-main}
SOURCE_ROOT=$(git rev-parse --show-toplevel)
BRANCH_COMMIT=$(git -C "${SOURCE_ROOT}" rev-parse "${BRANCH_REF}")
BASE_COMMIT=$(git -C "${SOURCE_ROOT}" merge-base "${BRANCH_COMMIT}" "${MAIN_REF}")
OUTPUT_DIR=$(mktemp -d "${TMPDIR:-/tmp}/stackit-sdk-generation.XXXXXX")
WORKTREE_DIR="${OUTPUT_DIR}/worktree"
echo "BASE_COMMIT: ${BASE_COMMIT}"
echo "BRANCH_COMMIT: ${BRANCH_COMMIT}"

cleanup() {
    if [[ -d "${WORKTREE_DIR}" ]]; then
        git -C "${SOURCE_ROOT}" worktree remove --force "${WORKTREE_DIR}" || true
    fi
}
trap cleanup EXIT

printf 'Generated SDKs will be retained in: %s\n' "${OUTPUT_DIR}"
printf 'Base commit: %s\n' "${BASE_COMMIT}"
printf 'Branch tip:  %s\n' "${BRANCH_COMMIT}"

# Use an isolated worktree so the caller's checkout and uncommitted work are
# never modified. Download the OAS once, before checking out the base commit.
git -C "${SOURCE_ROOT}" worktree add --detach "${WORKTREE_DIR}" "${BRANCH_COMMIT}" >/dev/null
(
    cd "${WORKTREE_DIR}"
    make download-oas
)

generate_sdk() {
    local label=$1
    local language=$2

    (
        cd "${WORKTREE_DIR}"
        make "generate-${language}-sdk"
    )
    cp -a "${WORKTREE_DIR}/sdk-repo-updated" "${OUTPUT_DIR}/${label}-${language}-sdk"
}

generate_all_sdks() {
    local label=$1

    generate_sdk "${label}" go
    generate_sdk "${label}" python
    generate_sdk "${label}" java
}

record_commit() {
    local label=$1
    local commit=$2

    printf '%s\t%s\t%s\n' \
        "${label}" \
        "${commit}" \
        "$(git -C "${SOURCE_ROOT}" show -s --format=%s "${commit}")" \
        >>"${OUTPUT_DIR}/commits.tsv"
}

: >"${OUTPUT_DIR}/commits.tsv"
git -C "${WORKTREE_DIR}" checkout --detach "${BASE_COMMIT}" >/dev/null
generate_all_sdks base
record_commit base "${BASE_COMMIT}"

printf '\n=== Branch tip: %s ===\n' "${BRANCH_COMMIT}"
git -C "${WORKTREE_DIR}" checkout --detach "${BRANCH_COMMIT}" >/dev/null
generate_all_sdks branch
record_commit branch "${BRANCH_COMMIT}"

printf '\nDone. Compare, for example:\n'
printf '  diff -qr %s %s\n' "${OUTPUT_DIR}/base-go-sdk" "${OUTPUT_DIR}/branch-go-sdk"
printf 'Commit labels:\n'
printf '  %s\n' "${OUTPUT_DIR}/commits.tsv"