Add kotlin extension to get HR time

app/src/main/java/eu/depau/ddroid/utils/NumberToTimeString.kt

@@ -0,0 +1,31 @@
+package eu.depau.ddroid.utils
+
+private val timeStrings = arrayOf("s", "m", "h", "d")
+private val timeDivs = arrayOf(60, 60, 24)
+
+fun <T> humanReadableTimeDelta(time: T): String where T : Number {
+    var dbTime = time.toDouble()
+    var outString = ""
+
+    for (i in 0..(timeDivs.size-1)) {
+        val div = timeDivs[i]
+        val str = timeStrings[i]
+
+        outString = "${(dbTime % div).toInt()}$str$outString"
+
+        if (dbTime < div)
+            return outString
+
+        outString = " $outString"
+        dbTime /= div
+    }
+
+    return "${dbTime.toInt()}${timeStrings[-1]} $outString"
+}
+
+fun Long.toHRTime() = humanReadableTimeDelta(this)
+fun Float.toHRTime() = humanReadableTimeDelta(this)
+fun Double.toHRTime() = humanReadableTimeDelta(this)
+fun Int.toHRTime() = humanReadableTimeDelta(this)
+fun Byte.toHRTime() = humanReadableTimeDelta(this)
+fun Short.toHRTime() = humanReadableTimeDelta(this)