[Filebeat] httpjson - add option for capturing a trace data

[andrewkroh]

Describe the enhancement:

As a user of the httpjson input that is developing configuration I would like to have a way of viewing the exact requests and responses associated with the input. When communicating in the clear with HTTP you can use tcpdump to see the raw requests and responses, but HTTPS is so common that this is rarely an option.

My proposal is to add an config option that writes timestamped requests and responses to a file via https://pkg.go.dev/net/http/httputil@go1.18.4#DumpRequestOut and https://pkg.go.dev/net/http/httputil@go1.18.4#DumpResponse. The file should automatically rotate based on size.

I considered adding an option to set a KeyLogWriter in the tls.Config to allow decrypting a pcap of HTTPS traffic, but I think a plain text file will be user to use.

Describe a specific use case for the enhancement or feature:

When a user needs to debug the httpjson input during development they would enable the trace logging option to see the complete request and responses captured to a file.

[elasticmachine]

Pinging @elastic/security-external-integrations (Team:Security-External Integrations)