zabbix: add server initscript and UI dependency

[danielfdickinson]

📦 Package Details

Maintainer: @champtar

Description:

• Adds a procd initscript for zabbix_server and adds related helper files
  • uses a zabbix_server uci conf to enable/disable startup
  • updates the default zabbix_server.conf to work with initscript
  • add a sysctl.d conf to set max-files more appropriately for zabbix_server
• Add a dependency on php8-mod-filter to zabbix-server-frontend
  • Many WebUI pages do not render without this module present, crippling the WebUI. Therefore, add this module as a dependency for the frontend.

If wished I could split this into two PRs, but that seems a bit excessive.

---

🧪 Run Testing Details

• OpenWrt Version: SNAPSHOT (r32228-a90fb76736)
• OpenWrt Target/Subtarget: bcm27xx/bcm2712
• OpenWrt Device: rpi-5

• Created a fresh image using ImageBuilder with the updated package and configured 'from scratch'.
• Tested a sysupgrade using another ImageBuilder generated image.

NOTE Was tested using MariaDB as PostgreSQL initialization is currently broken on master (#27228).

---

✅ Formalities

• I have reviewed the CONTRIBUTING.md file for detailed contributing guidelines.

If your PR contains a patch:

• [N/A] It can be applied using git am
• It has been refreshed to avoid offsets, fuzzes, etc., using

  make package/<your-package>/refresh V=s

• [N/A] It is structured in a way that it is potentially upstreamable

[danielfdickinson]

To save some time; the failing build on mips_24kc fails with:

Testing package apache-mod-php8 in version 8.4.15 from lang/php8
No pre-test.sh script available
( 1/10) Installing libapr (1.7.6-r1)
Bus error (core dumped)
Error: Process completed with exit code 138.

which is unrelated to Zabbix, except it is a dependency.