Remove unnecessary dependencies from Groonga installation guide

[otegami]

Remove KyTea and ZeroMQ (libzmq) installation steps from the PGroonga setup documentation. These dependencies are not required for using PGroonga with IvorySQL.

• KyTea: Rarely used and not required even with release-maximum preset
• ZeroMQ: Only required when using Groonga via groonga-suggest-httpd, not needed when using Groonga through PGroonga

Tested and confirmed that PGroonga works correctly without these dependencies in both package installation and source build scenarios on AlmaLinux 9 with IvorySQL 4.6 and PostgreSQL 17.6.

[github-actions]

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[yuanyl630]

Remove KyTea and ZeroMQ (libzmq) installation steps from the PGroonga setup documentation. These dependencies are not required for using PGroonga with IvorySQL.

• KyTea: Rarely used and not required even with release-maximum preset
• ZeroMQ: Only required when using Groonga via groonga-suggest-httpd, not needed when using Groonga through PGroonga

Tested and confirmed that PGroonga works correctly without these dependencies in both package installation and source build scenarios on AlmaLinux 9 with IvorySQL 4.6 and PostgreSQL 17.6.

Thank you so much not only for identifying areas to simplify the Groonga installation steps but also for ​​personally performing a complete installation and usage validation in an IvorySQL v4.6 and PostgreSQL 17.6 environment​​. The "Tested and confirmed" information you provided is incredibly valuable to us, giving us great confidence in PGroonga’s compatibility and stability with IvorySQL.