HPCC-10689 Allow "advanced" searches

Entering a WU (ECL/DFU) will open it, if it exists.
Prefixing "ecl:", "file:", "dfu:" will limit the scope of the search.

Fixes HPCC-10689

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #5662 from GordonSmith/HPCC-10689

HPCC-10689 Allow "advanced" searches

Reviewed-By: Miguel Vazquez <miguel.vazquez@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>