[ImageMonitor] Introduce chunking to circumvent file system limitations when recording image sequences

Increasing amounts of files in a folder (i.e. frames while recording) will significantly slow down ArmarX and even affect the operating system¹ (to a point where the recording cannot even be stopped due to ArmarX GUI freezing). No recordings longer than one minute are feasible because of this.

This MR introduces chunking, which means that per recording, for a given amount of frames, a dedicated folder is created.

Other fixes with this MR:

• Real time log printing about the status of the recording buffer queue
• Disabling the recording button as long as the recording buffer queue is being emptied
• Taking snapshots will no more create useless metadata files
• Total amount of frames is now written to metadata file
• Remove a blocking call in the GUI (use signals instead)

This MR is not API-breaking

Example of the structure of a RGB-D image sequence recording with 206 frames in nautilus:

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1. Except if the underlaying file system is XFS or so ↩