Provide extension on ILogger to log metrics

[tomkerkhove]

Provide extension on Serilog to log metrics:

Ideas are:

var context = new Dictionary<string, object>
{
    {ContextProperties.Customer, "Contoso"}
};

_logger.LogMetric("Orders Processed", 1, context);

Extension should allow you to provide contextual information by passing a dictionary, but should not be mandatory.

It should seemlessly integrate with the Azure Application Insight sink and track it as a "Metric".

A sample by Tom will be provided as a starting point.

[stijnmoreels]

Done?