Add craft-pkcs7: DER, X.509, CMS SignedData, PKCS #12, RFC 3161 and revocation from PdfCraft

* Add craft-pkcs7: DER, X.509, CMS SignedData, PKCS #12, RFC 3161 and revocation from PdfCraft

Moved from PdfCraft's crates/sign at 1d7a9f9f: der, x509, cms, pkcs12, timestamp,
revocation, keys, rsa_pad and ec512, with their unit tests, the integration tests
that need no PDF, and the test keys.

x509 no longer returns PdfCraft's worded sentences: signing_problem gives a
SigningProblem and build_chain_noted a Refused (reason and the two certificates).
The checks behind them are unchanged. Error is SignError without its PDF variants.

* craft-pkcs7: write the certificate serial verbatim in SignerInfo and ESSCertIDv2

A serial with its high bit set and no leading zero was written with one added, so
the signer identifier and the signing-certificate attribute named a different
number than the certificate has.

Ported from storytold/pdfcraft#6868. The test uses a certificate that really has
such a serial and also checks that the signer's certificate is found.

* craft-pkcs7: note why RIPEMD-160 is supported

---------

Co-authored-by: jonathanwxh-cell <jonathanwxh@gmail.com>

ATTRIBUTION.md

@@ -85,6 +85,7 @@ and the exact transfer revision are recorded in each vendored crate's SOURCE.jso
 | `crates/raster-codecs/src/xpm/x11_colors.rs` | X.Org Foundation and X11 contributors (X11 `rgb.txt` colour names and values, normalised into a lookup table) | <https://cgit.freedesktop.org/xorg/app/rgb/tree/rgb.txt>, via [PhotoCraft `crates/codecs`](https://github.com/storytold/photocraft/tree/63b641b55e54bf8f5c83efd977fdb16a2c255431/crates/codecs/src/codecs/xpm) | MIT (X.Org app/rgb) |
 | `crates/psd/tests/fixtures/atn/*.atn` (seven synthetic action sets, encoded field by field; `crates/psd/tests/fixtures/atn/README.md`) | PhotoCraft contributors | [PhotoCraft `crates/psd/tests/fixtures/atn`](https://github.com/storytold/photocraft/tree/63b641b55e54bf8f5c83efd977fdb16a2c255431/crates/psd/tests/fixtures/atn) | MIT OR Apache-2.0 |
 | `crates/lottie/tests/fixtures/` | EffectCraft contributors (original work: four hand-written Lottie JSON documents, written from the public Lottie format description; not exported from any Adobe product or third-party file) | [EffectCraft `crates/lottie/tests/fixtures`](https://github.com/storytold/effectcraft/tree/e18f48fb/crates/lottie/tests/fixtures) | MIT OR Apache-2.0 |
+| `crates/pkcs7/tests/data/` | PdfCraft contributors (original work: throw-away test keys and certificates made with OpenSSL 3 for these tests, as seven PKCS #12 files with the password `test` and two PEM certificates; they protect nothing; commands in `crates/pkcs7/tests/data/README.md`) | [PdfCraft `crates/sign/tests/data`](https://github.com/storytold/pdfcraft/tree/1d7a9f9f/crates/sign/tests/data) | MIT OR Apache-2.0 |
 | `crates/affinity/tests/support/corpus.tsv`, `crates/affinity/tests/support/affinity3-signatures.txt` (manifest and measured signatures only; the 51 documents are not bundled, `scripts/fetch-affinity-corpus.sh` downloads them outside the checkout) | The authors of each document: samuel-etver (vector-art), Seth A. Robinson (Patchy fixtures), Nick Beeuwsaert (AFDesignLoad), Jeremy Cantu (Branding), eviltwo (AssetStoreTemplate), Square (leakcanary) | each file's pinned upstream URL and SHA-256 in the manifest; list carried over from [VectorCraft `xtask/src/affinity_corpus.rs`](https://github.com/storytold/vectorcraft/blob/6e873b806c9d5b3f2b55f651df57bd97933b579a/xtask/src/affinity_corpus.rs) | CC0-1.0, MIT or Apache-2.0 (per file, in the manifest) |
 | `crates/raw/docs/coverage/adobe-cameras.tsv` | Facts (maker, model, extension, profile, minimum Camera Raw version) parsed by LightCraft contributors from Adobe's published list | [Adobe Camera Raw supported cameras](https://helpx.adobe.com/camera-raw/desktop/dng-and-file-formats/camera-raw-plug-supported-cameras.html), Wayback capture 20261003133011; moved from [LightCraft `docs/raw`](https://github.com/storytold/lightcraft/tree/5ff567a4a2e067bef1b6bce152c11e7f727ccbaf/docs/raw) | Facts, not copyrightable expression; the file is MIT OR Apache-2.0 |
 | `crates/raw/docs/coverage/{coverage,coverage-sweep,evidence,usage-weights}.tsv`, `coverage.py` | LightCraft contributors | [LightCraft `docs/raw`](https://github.com/storytold/lightcraft/tree/5ff567a4a2e067bef1b6bce152c11e7f727ccbaf/docs/raw) | MIT OR Apache-2.0 |