HPCC-10518 Add Roxie support to ECL Playground

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #5239 from GordonSmith/HPCC-10518_RoxiePlayground

HPCC-10518 Add Roxie support to ECL Playground

Reviewed-By: Miguel Vazquez <miguel.vazquez@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>