JsonExporter: make Json export more extensible.

[ptr1120]

Hello,
I would like to add additional data to the existing JSON BenchmarkDotNet report, but there is currently no possibility to enrich the report. That's why I separated ExportToLog into report creation (ExportToLog) and further virtual report data generation methods (CreateLog).

Best regards
Peter

@adamsitnik Sorry for closing my initial pull request (#1915). I applied your suggested change (Rename CreateLog-> GetDataToSerialize) and had an issue rebasing this change into my initial commit.

[adamsitnik]

@ptr1120 thank you again!

[adamsitnik]

btw speaking of #1915: I've solved the merge conflict via GitHub website, this has pushed some changes to your fork and when you tried to rename the method you most probably got rejected and force pushed. The best way to avoid such issues is to always create a new branch for every PR. Then if the PR gets rejected or the something bad happens with git your main branch remains clean and you can create a new one.

How to create a new branch:

git checkout -b $newBranchName

How to sync your branch:

git remote add upstream https://github.com/dotnet/BenchmarkDotNet
git fetch upstream
git merge upstream/master

[ptr1120]

@adamsitnik thanks for the explanation.