Several minor tweaks for the Settings page

[DL6ER]

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Several minor tweaks for the Settings page

• Add 'Flush Logs' button also to the Query Logging dialog box
• Add tooltips to the advanced DNS check boxes
• Resolve "Undefined index: DHCP_LEASETIME" warning
• Fix indentation of "Privacy mode" check box
• Show warning if PHP has been compiled without IPv6 support (compile flag --disable-ipv6)

This template was created based on the work of udemy-dl.

[AzureMarker]

Approved