jinja2utils: functions and filter to context
- Like for bfe_* it allows the admin user to add new functions, template_context_functions (tfn), to display content within a jinja template.
- Adds the possibility to create new filters template_context_filters (tfi).
Signed-off-by: Esteban J. G. Gabancho <esteban.gabancho@cern.ch>
Co-authored-by: Jiri Kuncar <jiri.kuncar@cern.ch>