HPCC-10735 Support different query classes in the regression suite

Add new run CLI parameters: --runclass and - --excludeclass
Add run/exl test class handler to ecl file
Add test class run/excl checking in suite building
Change content of excluded file log to refer why that file is excluded

Create environment log file (from args and config) for every
(setup/query/run) execution (to help tracing)

Update README.rst and built-in help.

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>