WARC writer support HTTP/2

[sebastian-nagel]

Nutch' protocol-okhttp supports HTTP/2 since its introduction in 2018. Alone, the WARC writer does not.

The following points need to be addressed:

• protocol-okhttp: record HTTP and SSL/TLS versions, see NUTCH-3062
• ensure that the HTTP headers in the WARC request and response records use "HTTP/1.1" in the request resp. status line. This is required for backward-compatibility with WARC readers. Cf. Do not use "http/2" protocol version in HTTP headers in WARC files news-crawl#42 and [WARC] Backward compatible storage of HTTP/2 headers apache/incubator-stormcrawler#1010.
• save the true protocol version in the WARC-Protocol field, see WARC-Protocol field proposal iipc/warc-specifications#42
• also save the SSL/TLS version in a second WARC-Protocol field
• if required, normalize the protocol name(s)
• save the cipher suite in the WARC-Cipher-Suite field, see WARC-Cipher-Suite field proposal iipc/warc-specifications#86
• optionally add a counter for metrics which protocol versions are used

[sebastian-nagel]

Implemented by #30. Successfully tested during CC-MAIN-2024-30, HTTP/2 fetching enabled for 58 segments.