Have "-l syslog" and "log_localtime=true" honor the env TZ data or "/etc/localtime"

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### Prerequisites

Please answer the following questions for yourself before submitting an issue. **YOU MAY DELETE THE PREREQUISITES SECTION.**

- [X ] I am running the latest version
- [ X] I checked the documentation and found no answer
- [ X] I checked to make sure that this issue has not already been filed

### Problem Description
When both "-l syslog" and "log_localtime=true" , system log does not properly parse the available TZ data for the correct time zone. Instead, UTC is used.
Here is an example of what the problem looks like.

`Jan 26 00:38:41 RT-AX88U-C7C0 dnsmasq[5042]: using 11 more local addresses`
`Jan 26 00:38:41 RT-AX88U-C7C0 custom_script: Running /jffs/scripts/service-event-end (args: restart dnsmasq)`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.244226 [info] Starting the DNS proxy server`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.244345 [info] Ratelimit is enabled and set to 20 rps`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.244367 [info] The server is configured to refuse ANY requests`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.244385 [info] DNS cache is enabled`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.244492 [info] MaxGoroutines is set to 300`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.244533 [info] Creating the UDP server socket`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.244700 [info] Listening to udp://[::]:53`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.244720 [info] Creating a TCP server socket`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.244810 [info] Listening to tcp://[::]:53`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.245790 [info] Entering the tcp listener loop on [::]:53`
`Jan 26 05:38:42 RT-AX88U-C7C0 AdGuardHome[4920]: 2022/01/26 05:38:42.246830 [info] Entering the UDP listener loop on [::]:53`
`Jan 26 00:39:05 RT-AX88U-C7C0 rc_service: httpd 1321:notify_rc start_scmerlingetaddonpages;start_scmerlingetcronjobs`
`Jan 26 00:39:05 RT-AX88U-C7C0 custom_script: Running /jffs/scripts/service-event (args: start scmerlingetaddonpages)`
`Jan 26 00:39:05 RT-AX88U-C7C0 custom_script: Running /jffs/scripts/service-event-end (args: start scmerlingetaddonpages)`
`Jan 26 00:39:05 RT-AX88U-C7C0 custom_script: Running /jffs/scripts/service-event (args: start scmerlingetcronjobs)`
`Jan 26 00:39:05 RT-AX88U-C7C0 custom_script: Running /jffs/scripts/service-event-end (args: start scmerlingetcronjobs)`
`Jan 26 00:39:07 RT-AX88U-C7C0 rc_service: httpd 1321:notify_rc start_addon_settings;start_connmoncustomactionlist;st`

### Proposed Solution
The solution to the problem would for the GO, or what ever mechanisms AdGuardHome uses, to be able to properly parse the environment TZ data. For example,
`export TZ=$(cat /etc/TZ)`
or have AdGuardHome parse for
`/etc/localtime`.

### Alternatives Considered
Here is an example from the go.dev source.

https://go.dev/src/time/zoneinfo_unix.go