Fix template FileField reading

This merge request fixes all templates where a FileField content was read directly rather than using the associated property who would give the correct output.

Fixes #566 (closed)

changed milestone to %Code cleanup

added bug confirmed labels

added 9 commits

• 53db39a6...9e9143cb - 5 commits from branch django3_migration
• a83499b3 - [algorithms][templates] Use file field property to read content
• f8397cfc - [dataformats][templates] Use file field property to read content
• 426e27d1 - [libraries][templates] Use file field property to read content
• 9460816e - [plotters][templates] Use file field property to read content

Compare with previous version

enabled an automatic merge when the pipeline for 9460816e succeeds

merged

mentioned in commit a3259630