HPCC-8854 Performance Improvements

Load graph pages on demand.
Load result pages on demand.
Load source files pages on demand.
Load schemas on demand.
Fix page loading issue with DFU workunits.
Common up "Grid->Details" pattern (TODO:  WUQuery etc.)
Use cached version of graphs if available.

Fixes HPCC-8854
Fixes HPCC-8641

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>