add proc id to RFC3164

[dicolanl]

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Add support for process ID in RFC 3164. per https://tools.ietf.org/html/rfc3164#section-5.3 process id would be enclosed in []

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when using -processid with -rfc3164, send the message with process id in []

Examples of how the solution would work
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Send-SyslogMessage -Server 172.17.116.142 -Message "CEF:0|Microsoft|Powerhsell|6.2|ID|PWSH|6|src=8.8.8.8 dst=67.166.178.142" -Severity Informational -Facility local7 -RFC3164 -Port 5514 -ProcessID 123

output: <190>Feb 24 11:05:17 172.17.116.129 PowerShell[123]: CEF:0|Microsoft|Powerhsell|6.2|ID|PWSH|6|src=8.8.8.8 dst=67.166.178.142
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