Show how to bind options to a specific config section

[diddledan]

• fixes issue #867.
• Based on suggested code from @danroth27.

Code builds successfully using dotnet.exe command line utility.

[dnfclas]

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[dnfclas]

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[Rick-Anderson]

@divega please review

[divega]

Please have @HaoK review instead.

[HaoK]

Looks fine, maybe we should consider updating the parent options to also have a MySubOptions property, to demonstrate that nested complex options bind recursively.

[Rick-Anderson]

Updated #829 with consider updating the parent options to also have a MySubOptions property, to demonstrate that nested complex options bind recursively.

@rachelappel please resolve merge conflict and merge.

[rachelappel]

Merged b1faeda