WIP refactoring: caches

app/scodoc/ImportScolars.py

app/scodoc/debug.py

app/scodoc/notes_table.py

app/scodoc/sco_apogee_csv.py

app/scodoc/sco_archives.py

app/scodoc/sco_bulletins.py

app/scodoc/sco_bulletins_json.py

app/scodoc/sco_bulletins_pdf.py

app/scodoc/sco_bulletins_signature.py

app/scodoc/sco_bulletins_xml.py

app/scodoc/sco_core.py

app/scodoc/sco_debouche.py

app/scodoc/sco_edit_formation.py

app/scodoc/sco_edit_ue.py

app/scodoc/sco_evaluations.py

app/scodoc/sco_export_results.py

app/scodoc/sco_formsemestre.py

app/scodoc/sco_formsemestre_edit.py

app/scodoc/sco_formsemestre_exterieurs.py

app/scodoc/sco_formsemestre_inscriptions.py