Add config value for how many minimal process report should be kept in the history

A minimal history is a history entry without log and prelude.

The corresponding config entry is ffmpeg.log.max_minimal_history. This value is
added on top of the ffmpeg.log.max_history value. I.e. the latest max_history
entries contain the log and prelude, and the remaining entries don't have the
log and prelude. In total there are max_minimal_history+max_history history
entries.

If you want no history, set both values to 0.
If you want only full history, set max_minimal_history to 0.
If you want only minimal history, set max_history to 0.

app/api/api.go

@@ -491,14 +491,15 @@ func (a *api) start() error {
 	}
 
 	ffmpeg, err := ffmpeg.New(ffmpeg.Config{
-		Binary:           cfg.FFmpeg.Binary,
-		MaxProc:          cfg.FFmpeg.MaxProcesses,
-		MaxLogLines:      cfg.FFmpeg.Log.MaxLines,
-		LogHistoryLength: cfg.FFmpeg.Log.MaxHistory,
-		ValidatorInput:   validatorIn,
-		ValidatorOutput:  validatorOut,
-		Portrange:        portrange,
-		Collector:        a.sessions.Collector("ffmpeg"),
+		Binary:                  cfg.FFmpeg.Binary,
+		MaxProc:                 cfg.FFmpeg.MaxProcesses,
+		MaxLogLines:             cfg.FFmpeg.Log.MaxLines,
+		LogHistoryLength:        cfg.FFmpeg.Log.MaxHistory,
+		LogMinimalHistoryLength: cfg.FFmpeg.Log.MaxMinimalHistory,
+		ValidatorInput:          validatorIn,
+		ValidatorOutput:         validatorOut,
+		Portrange:               portrange,
+		Collector:               a.sessions.Collector("ffmpeg"),
 	})
 	if err != nil {
 		return fmt.Errorf("unable to create ffmpeg: %w", err)