[#2482] Add prefix/suffix for createFolder and writeFileContent.

Problem
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It would be nice to add a prefix on temp folders so that when debuging is much easier to identify their purpose.

Changes
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Add prefix and suffix to tempFolder just like we have for tempFile

As a drive by add a helper method to write content to a file.

How to test
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reviewers: @alibotean 

check that changes make sense.

I had to release 0.30.1 since for first release I forgot to merge master.

thanks!
I see your point. Will keep this in mind.