Make certmanager a drop-in for the Python script

Puppet calls /usr/local/bin/certmanager from generate() with combine: true, so
the CLI must take the common name positionally and keep stderr clean or the
catalog compile dies on a parsejson error.

- Flatten the CLI: drop the pki subcommand, add -a/-i/-e/-c/--json
- Emit ca_certificate so vault.pp stops writing undef to that file
- Read output_path from under vault:, where Puppet writes it
- Bound every Vault request with a timeout; exit non-zero on failure
- Gate TLS verification on vault.tls_skip_verify (default true)
- Restrict auth to approle and kubernetes, no fallback between them
- Remove the SSH half; add Woodpecker CI, nfpm RPM and completions

scripts/build-rpm.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+#
+# Package the (already built) certmanager binary into an RPM with nfpm,
+# bundling generated bash/zsh/fish shell completions.
+# Usage: scripts/build-rpm.sh [version]   (version defaults to $CI_COMMIT_TAG)
+#
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "${ROOT_DIR}"
+
+VERSION="${1:-${CI_COMMIT_TAG:-0.0.0-dev}}"
+VERSION="${VERSION#v}" # strip a leading v
+BINARY="certmanager"
+DIST="dist"
+
+if [ ! -f "${DIST}/${BINARY}" ]; then
+  echo "ERROR: ${DIST}/${BINARY} not found; run 'make build' first" >&2
+  exit 1
+fi
+
+# Generate shell completions from the freshly built binary so they always match
+# the shipped flags.
+COMP_DIR="${DIST}/completions"
+mkdir -p "${COMP_DIR}"
+"./${DIST}/${BINARY}" completion bash >"${COMP_DIR}/${BINARY}.bash"
+"./${DIST}/${BINARY}" completion zsh >"${COMP_DIR}/_${BINARY}"
+"./${DIST}/${BINARY}" completion fish >"${COMP_DIR}/${BINARY}.fish"
+
+export PACKAGE_NAME="${BINARY}"
+export PACKAGE_VERSION="${VERSION}"
+export PACKAGE_RELEASE="1"
+export PACKAGE_ARCH="amd64"
+export PACKAGE_PLATFORM="linux"
+export PACKAGE_DESCRIPTION="Issues Vault PKI certificates for Puppet-managed nodes; drop-in replacement for the Python certmanager script"
+export PACKAGE_MAINTAINER="Ben Vincent <ben@unkin.net>"
+export PACKAGE_HOMEPAGE="https://git.unkin.net/unkin/certmanager"
+export PACKAGE_LICENSE="MIT"
+
+envsubst <packaging/nfpm.yaml >"${DIST}/nfpm.yaml"
+nfpm pkg --config "${DIST}/nfpm.yaml" --target "${DIST}" --packager rpm
+
+echo "Built:"
+ls -1 "${DIST}"/*.rpm