Destructure support

[MV10]

Added support for destructure With and max-limit settings, also opening up destructuring features to additional configuration through extension methods in other packages, as discussed in #106.

• ConfigurationReader:
  • add ApplyDestructuring
  • add FindDestructureConfigurationMethods
  • added surrogates for several destructure config methods
  • add comments explaining method-level surrogates
  • renamed FindConfigurationMethods to FindConfigurationExtensions
• three unit tests modeled on Serilog's own destructure tests
• README updated with a few lines of JSON demonstrating the settings
• changes to sample program
  • config for Destructure max string length and max collection depth
  • log events to demonstrate Destructure config
  • comment explaining Filter syntax is from S.F.Expressions package

Update

• renamed FindConfigurationExtensions toFindConfigurationExtensionMethods
• added IDestructuringPolicy example to sample program and README docs

[tsimbalar]

nitpicking : Maybe FindConfigurationExtensionMethods instead of FindConfigurationExtensions is clearer (extensions are not a thing in C#, but extension methods are :p)

[MV10]

I considered the longer name, but hadn't considered the point you raise. I'll make the change (but will wait a bit for other feedback). Thanks.

[tsimbalar]

There is currently an open issue in Serilog.Settings.AppSettings for support of .Destructure.* methods : serilog/serilog-settings-appsettings#20 .

It would be good to try and have the same level of support for Destructuring in both settings providers.

[MV10]

@tsimbalar Since you referenced the AppSettings thread, for anyone doing work there I'll add this to illustrate how the destructuring section looks for this Configuration package. (This is in this PR's README but it's more discoverable here while this PR is in-flight.)

Within the Serilog section:

    "Destructure": [
      { "Name": "With", "Args": { "policy": "Sample.CustomPolicy, Sample" } },
      { "Name": "ToMaximumDepth", "Args": { "maximumDestructuringDepth": 4 } },
      { "Name": "ToMaximumStringLength", "Args": { "maximumStringLength": 100 } },
      { "Name": "ToMaximumCollectionCount", "Args": { "maximumCollectionCount": 10 } }
    ],

[MV10]

@tsimbalar or @nblumhardt Can we get this one wrapped up? Not sure who can merge here...

[tsimbalar]

Looks good to me !

I have updated my "documentation" repo with the nuget package from this PR to validate the expected behavior and it worked like a charm : https://github.com/tsimbalar/serilog-settings-comparison/blob/master/docs/README.md#custom-destructuring 🎉

I'll merge it !