Add option to use Shared Memory for MSSQL connections

[Saeid-Abadi]

Some MSSQL servers have TCP/IP disabled, which prevents the current MSSQL checks from connecting.

System.Data.SqlClient.SqlConnection supports connections via the Shared Memory protocol, which works for local MSSQL instances even when TCP/IP is disabled. It would be useful to add an optional parameter to Open-IcingaMSSQLConnection to allow using Shared Memory instead of TCP/IP.

This could be implemented by adjusting the connection string (e.g. Server=localhost;) when the option is enabled. This would allow monitoring MSSQL instances where TCP/IP is disabled and could also reduce connection overhead for local checks.

[Saeid-Abadi]

ref/NC/890709