Add personal notes summary to week view

In the group week view:

• In the view, get all personal notes related to members of the selected group and the selected week
• For each person, count the absent lessons, sum up tardiness, and list all the remarks that are available
• In the template, render one entry for every person in the group with the summarised data

changed milestone to %1.0a0

added part::backend part::frontend prio::2 labels

changed title from Add personal nots summary to week view to Add personal notes summary to week view

marked the checklist item In the view, get all personal notes related to members of the selected group and the selected week as completed

marked the checklist item For each person, count the absent lessons, sum up tardiness, and list all the remarks that are available as completed

marked the checklist item In the template, render one entry for every person in the group with the summarised data as completed

closed via commit 98984611