Bugfix/udp tcp sink fixes #155

[EEParker]

• Embedd sources as Splunk.Logging.Common.Core is not signed upstream
• netstandard2.1 is not supported by Splunk.Logging.Common.Core
• Add a TCP socket unit test to ensure assembly can load

Fixes #155

[EEParker]

Just a note, I'm not sure this is the correct solution, but I waned to put it out here for review and suggestions.

[EEParker]

I reworked this and embedded the sources from the upstream unsigned library. This allows this assembly to be signed. @VictorioBerra

[EEParker]

Addresses #188