HPCC-9881 Add default context menu support

Add default context menu support for "Refresh" and "Open".
Add method for derived pages to enhance menu.
Add default messages for loading and no data.

Fixes HPCC-9881

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #4764 from GordonSmith/HPCC-9881

HPCC-9881 Add default context menu support 

Reviewed-By: Miguel Vazquez <miguel.vazquez@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>