Switch doc tests to Ubuntu on pull request builds

Use CalMuonDeadTime in systemtest

Fix Indirect Diffraction plotting

Allows just the includes/libs to be fetched and also shallow clones
both repositories.

Re #12732

Fixes for crashes when running doc tests on Windows

Add XScaling parameter to TabulatedFunction

VESUVIO l1 and theta resolution routine

Revert "Revert "Fix squish tests""

The documentation only requires the standard test data.

The windows ones don't match yet

Point issue tracking to github

LoadCalFile creates new calibration workspace

Create new diffraction config object

Calculate chi squared over dof

The differences are very minor.

Allow an arbitrary trailing string on the qwt version

Eraser cursor invisible

Help strings in parameter classes