improvements to ScalarEq, EulerEq, SRHD

Accumulated various changes

• draft for 2d SRHD evolution
• rework ScalarEq 1d to use new broadcast routines
• use force=true on callbacks before evolution to make sure initial data is outputted
• updated ref tests because of previous point
• rework EulerEq and fix bdry conditions to be able to evolve sod shock tube test with entropy viscosity

added output refactor tests labels

enabled an automatic merge when the pipeline for 5b8d4bcb succeeds

merged

mentioned in commit 72051148

mentioned in commit 9033b247

mentioned in merge request !51 (closed)