http: logs custom headers in a subobject

[catenacyber]

Link to redmine ticket:
https://redmine.openinfosecfoundation.org/issues/5320

Describe changes:

• http: logs custom headers in a subobject

To avoid collisions, for instance for content_range

With this PR, the output will be

    "content_range": {
      "raw": "bytes 10-20/69",
      "start": 10,
      "end": 20,
      "size": 69
    },
    "response_headers": [
      {
        "name": "Content-Range",
        "value": "bytes 10-20/69"
      }
    ]

instead of

    "content_range": {
      "raw": "bytes 10-20/69",
      "start": 10,
      "end": 20,
      "size": 69
    },
   "content_range": "bytes 10-20/69"

response_headers is already used with the config option dump-all-headers

suricata-verify-pr: 1026

Replaces #8672 with better code style for a variable name

[catenacyber]

OISF/suricata-verify#1026

[suricata-qa]

WARNING:

field	baseline	test	%
	SURI_TLPW1_stats_chk
.tcp.rst	113181	145112	128.21%

Pipeline 13113

[victorjulien]

Merged in #8951, thanks!

I think this needs an upgrade doc entry still btw.

[catenacyber]

Indeed, see #8978