Add checksum validation on artifact upload

[robherley]

Relevant Issues:

• https://github.com/github/c2c-actions-checks/issues/301
• https://github.com/github/c2c-actions-checks/issues/391

tl;dr adds base64 encodings of the CRC64 and MD5 to the headers of a chunk upload:

x-actions-results-crc64
x-actions-results-md5

Recently we've been running into issues when artifacts are getting corrupted during the upload process. This is extremely rare (seen < 1% during my tests) but happens nonetheless. There still needs to be more investigation as to why these are being corrupted, but we've narrowed the problem areas to be between the upload and file container service handler after isolated testing with md5 checksum headers.

This PR adds a CRC64 and MD5 checksum to the header. Since NodeJS's crypto library (openssl bindings) doesn't have CRC64, I added a simple implementation based on Go's hash/crc64 pkg. Also this is tailored to the CRC polynomial used by azure storage. We're already using this same polynomial places deeper in the stack.

I ran some benchmarks and this CRC64 implementation is a bit faster than sha256/md5:

crc64 x 145,627 ops/sec ±8.33% (79 runs sampled)
md5 x 76,392 ops/sec ±12.44% (69 runs sampled)
sha256 x 65,982 ops/sec ±14.55% (62 runs sampled)
Fastest is crc64

[yacaovsnc]

[wesdgray]

I ran into this problem with a service that handled large file uploads and the root cause was that our continuous deployment was killing our containers after a shorter than expected timeout. In our case, during deployment, hosts are taken out of the pool and in-flight requests are allowed to finish but it was not known to us at the time that a timeout was even in effect.

Also if you're wondering how I even stumbled upon this: https://youtu.be/9qljpi5jiMQ?t=722