Change namespace to Microsoft.ApplicationInsights.Profiler.*

[xiaomi7732]

This will make logging easy & consistent.

[xiaomi7732]

• [x] Update core code;
• [x] Update AspNetCore header;
• [x] Update uploader;
• [x] Update examples/instructions for debugging;

[xiaomi7732]

Code change has been released in 2.2.0-beta6.