Improve display of activities when scrolling

User story: Feedback from Willi, group in Fürth

Name of days in „actvities“:
PC web-version shows the name of the next day in the middle of the main window and when you scroll over 10 – 15 activities on every day you overlook the name oft the next day and you loose the orientation on what day you are now.

From: Log: incoming feedback in raw format - #5 by bruno

Also from Luxemburg, via Daniel on github

It would be nice to have a filter by day of the week (Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday) to the activities page as they can only be active on a few days of the week.

Complexity: not very complex

Outcomes (or what needs to be done to move forward): design a simple solution

I noticed myself the same issue before, since in my group some days are quite busy too.

Possible solution: fix the day on the top as you scroll

Another solution I suggested to the filter by weekdays above is to have a calendar view