filter_sysinfo: add filter sysinfo plugin

[nokute78]

This patch is to add a new plugin filter_sysinfo.
It is to add system information like hostname, os version and fluent-bit version.

Some properties are supported by specific platform.

Key	Description	Supported platform
fluentbit_version_key	Specify the key name for fluent-bit version.	All
os_name_key	Specify the key name for os name. e.g. linux, win64 or macos.	All
hostname_key	Specify the key name for hostname.	All
os_version_key	Specify the key name for os version. It is not supported on some platforms.	Linux
kernel_version_key	Specify the key name for kernel version. It is not supported on some platforms.	Linux

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Enter [N/A] in the box, if an item is not applicable to your change.

Testing
Before we can approve your change; please submit the following in a comment:

• Example configuration file for the change
• Debug log output from testing the change

• Attached Valgrind output that shows no leaks or memory corruption was found

If this is a change to packaging of containers or native binaries then please confirm it works for all targets.

• [N/A] Run local packaging test showing all targets (including any new ones) build.
• [N/A] Set ok-package-test label to test for all targets (requires maintainer to do).

Documentation

• Documentation required for this feature

Backporting

• [N/A] Backport to latest stable release.

Configuration

[INPUT]
    Name dummy

[FILTER]
    Name sysinfo
    Match *
    fluentbit_version_key flb_ver
    os_name_key os
    hostname_key hostname
    os_version_key os_ver
    kernel_version_key os_ver

[OUTPUT]
    Name stdout
    Match *

Debug/Valgrind output

$ valgrind --leak-check=full bin/fluent-bit -c b.conf
==12559== Memcheck, a memory error detector
==12559== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==12559== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==12559== Command: bin/fluent-bit -c b.conf
==12559== 
Fluent Bit v2.2.0
* Copyright (C) 2015-2023 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

[2023/10/30 08:35:15] [ info] [fluent bit] version=2.2.0, commit=e590c8b221, pid=12559
[2023/10/30 08:35:15] [ info] [storage] ver=1.2.0, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2023/10/30 08:35:15] [ info] [cmetrics] version=0.6.4
[2023/10/30 08:35:15] [ info] [ctraces ] version=0.3.1
[2023/10/30 08:35:15] [ info] [input:dummy:dummy.0] initializing
[2023/10/30 08:35:15] [ info] [input:dummy:dummy.0] storage_strategy='memory' (memory only)
[2023/10/30 08:35:15] [ info] [output:stdout:stdout.0] worker #0 started
[2023/10/30 08:35:15] [ info] [sp] stream processor started
[0] dummy.0: [[1698622516.019936933, {}], {"message"=>"dummy", "flb_ver"=>"2.2.0", "os"=>"linux", "hostname"=>"taka-VirtualBox", "os_ver"=>"#35~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Fri Oct  6 10:23:26 UTC 2", "os_ver"=>"6.2.0-35-generic"}]
^C[2023/10/30 08:35:17] [engine] caught signal (SIGINT)
[0] dummy.0: [[1698622517.021173524, {}], {"message"=>"dummy", "flb_ver"=>"2.2.0", "os"=>"linux", "hostname"=>"taka-VirtualBox", "os_ver"=>"#35~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Fri Oct  6 10:23:26 UTC 2", "os_ver"=>"6.2.0-35-generic"}]
[2023/10/30 08:35:17] [ warn] [engine] service will shutdown in max 5 seconds
[2023/10/30 08:35:17] [ info] [input] pausing dummy.0
[2023/10/30 08:35:17] [ info] [engine] service has stopped (0 pending tasks)
[2023/10/30 08:35:17] [ info] [input] pausing dummy.0
[2023/10/30 08:35:18] [ info] [output:stdout:stdout.0] thread worker #0 stopping...
[2023/10/30 08:35:18] [ info] [output:stdout:stdout.0] thread worker #0 stopped
==12559== 
==12559== HEAP SUMMARY:
==12559==     in use at exit: 0 bytes in 0 blocks
==12559==   total heap usage: 1,788 allocs, 1,788 frees, 1,166,380 bytes allocated
==12559== 
==12559== All heap blocks were freed -- no leaks are possible
==12559== 
==12559== For lists of detected and suppressed errors, rerun with: -s
==12559== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[nokute78]

User requested #8052

[nokute78]

Doc PR is fluent/fluent-bit-docs#1249