Combine files in multiple mode view to a new custom group with custom name

[BridgeAR]

Feature request

Description

As a user, I want to have short logical names in multiple mode so that I do not have a full screen only with the filename.

Acceptance criteria

• When loading multiple mode where the resulting filename is longer than e.g., 30 characters, ask the user to bind the files logically to a group with a name that the user may define in a popup window (the same window where the user is asked if they want to group the files together)
• Indicate the grouping by using indented checkboxes similar to the examples with angular material (see picture one)
• Use the defined name as the group name and show that as filename (see picture two as how it should not look like)