Improve certificate rotation process

[arudell]

Description

Summary of changes:

• Moved Start-SdnServerCertificateRotate and Start-SdnMuxCertificateRotate to SdnDiag.NetworkController module and updated to execute on NetworkController directly
• Created a new Start-SdnNetworkControllerRestCertificateRotate to handle rotating of the rest and encryption certificate.
• Moving appropriate logic for certificate generation / parsing of pfx files to each respective function

Change type

• Bug fix (non-breaking change)
• Code style update (formatting, local variables)
• New Feature (non-breaking change that adds new functionality without impacting existing)
• Breaking change (fix or feature that may cause functionality impact)
• Other

Checklist:

• My code follows the style and contribution guidelines of this project.
• I have tested and validated my code changes.