Fix clang-tidy modernize-use-override issues

This uses the -fix option on clang-tidy to automatically fix all
the cases not using override that have crept into Mantid.

Fix clang-tidy misc-unused-using-decls issues

It looks like clang-tidy stripped out these using decls no realising
that the type is required in the GET_POINTER_SPECIALIZATION macros on
windows.

This uses the -fix option on clang-tidy to automatically fix all
the unused usings declarations that have crept into Mantid.

Moved TofEvents from DataObjects to Types::Events

Tidy help/message strings in engineering diffraction UI

Fix use of std::move with const in ScanningWorkspaceBuilder

A couple of things found in #20587 that didn't seem worthy of opening a
ticket for someone else to do.

Flake8 issues inelastic direct

Remove a cppcheck error

Replace celebration splash screen

Fix RayTracerTesterTestPerformance indicated issues 

Clang-tidy modernize-use-nullptr

Refs #20645. Fixed typo in the Bin2DPowderDiffraction documentation.

InstrumentRayTracer now has local cache from which to fetch bounding boxes.