Added a test for hiding report summary

Implementing a new API parameter that can be used to hide the report
summary (this is a real-life use case from a user organization). Added a
test that uploads report with the defined parameter.
Added column hide_summary to test session

Added column that, when set to true, causes result summary to be hidden.
Hide report summary if defined so

If hide_summary is set to true the report summary section is not shown.
This was requested by a user organization. It was not just hidden using
css because in most cases the summary should be shown. This feature is
sort of prequisite for another feature request of enabling metrics
reporting on test report level (similar to measurements but on higher
level).