Improvements to Windows interface logging

[notr1ch]

Description

Improve logging of network interface used for RTMP transmission on Windows:

• Properly report > 1gbps speed by using GetIfEntry2
• Log RX / TX speeds separately
• Log interface error counters if non-zero

Motivation and Context

Saw a log that had "4294 mbps" and got annoyed.

How Has This Been Tested?

Tested locally with debugger.

Types of changes

• Tweak (non-breaking change to improve existing functionality)

Checklist:

• [x] My code has been run through clang-format.
• [x] I have read the contributing document.
• [x] My code is not on the master branch.
• [x] The code has been tested.
• [x] All commit messages are properly formatted and commits squashed where appropriate.
• [x] I have included updates to all appropriate documentation.