Use Common Log Format for logging output

[jsoriano]

Use Combined Log Format, so package-registry logs can be parsed with the
same tools that can be used to parse logs of common web servers such as
Apache or nginx.

This log format is not much more verbose and includes additional information:

• Timezone in the timestamp.
• HTTP method, HTTP version, status code and response size.
• Referer (when available).
• User agent (when available).

This changes the log format from:

2022/03/01 10:12:31 source.ip: 127.0.0.1:42334, url.original: /
2022/03/01 10:12:38 source.ip: 127.0.0.1:42342, url.original: /search

To:

127.0.0.1 - - [01/Mar/2022:10:28:28 +0100] "GET / HTTP/1.1" 200 71 "" "curl/7.58.0"
127.0.0.1 - - [01/Mar/2022:10:28:57 +0100] "GET /search HTTP/1.1" 200 7912 "" "curl/7.58.0"

[elasticmachine]

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• Start Time: 2022-03-01T09:42:54.678+0000

• Duration: 5 min 38 sec

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🤖 GitHub comments

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[mtojek]

I'm not sure if it isn't on purpose. EPR logs on the infra side might be configured to process them this way.

[jsoriano]

Discussed offline with @ruflin, lets move to JSON ECS logs so no ingest pipeline is needed for ingestion in ES.