#519 Match type namespace prefix as well when building LogLevels

[wdolek]

Related to #519

Description of changes:
Adding support of namespace prefixes as well, alongside of wildcard support. Namespace prefixing is common in .NET, see issue.

With this change, log levels can be configured like this:

    "LogLevel": {
      "Default": "Debug",
      "Microsoft": "Information",
      "System": "Warning",
      "System.Net": "Information",
      "System.Net.Http": "Debug"
    }

Wildcards are still supported, in fact, namespace prefix uses very same data structure to match category. (technically wildcard "*" is just removed and behavior is the same for both ways)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[normj]

Version 3.0.0 of Amazon.Lambda.Logging.AspNetCore has been released with the PR.