HPCC-10512 Allow regression suite to contain summary queries

Add new tag //nokey and handling implementation
Put output of "no key file compared" test case to logfile.
Update README.rst

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>
Merge pull request #5262 from AttilaVamos/HPCC-10512-improvement

HPCC-10512 Allow regression suite to contain summary queries

Reviewed-By: Gavin Halliday <gavin.halliday@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>