Add IOutstationApplication::OnConfirmProcess to C++, C#, and Java

[jadamcrain]

This is my first stab at adding this feature. It was straightforward as the callback is only invoked from two places in OutstationStates.cpp

We might consider adding some tests to this PR to verify.

[codecov]

Codecov Report

Merging #403 into release will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           release     #403      +/-   ##
===========================================
+ Coverage    51.69%   51.75%   +0.05%     
===========================================
  Files          456      456              
  Lines        13602    13609       +7     
===========================================
+ Hits          7032     7043      +11     
+ Misses        6570     6566       -4     

Impacted Files	Coverage Δ
cpp/lib/src/outstation/event/EventBuffer.h	100.00% <ø> (ø)
...clude/opendnp3/outstation/IOutstationApplication.h	12.50% <100.00%> (+3.80%)	⬆️
cpp/lib/src/outstation/OutstationStates.cpp	73.33% <100.00%> (+1.05%)	⬆️
cpp/lib/src/outstation/event/EventBuffer.cpp	50.00% <100.00%> (+0.76%)	⬆️
cpp/lib/src/channel/IOHandler.cpp	80.15% <0.00%> (+3.05%)	⬆️

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