Metrics takes too much memory by default

[pmetel]

It seems that 6 basic Metrics can take over 250MB of the heap, after some time.
This is due TimeSeries default SlidingWindowList is truncated above 7 * 24 * 3600 * 2.1

Memory profiler shows me that SlidingWindowList with 758_712 elements took 27_520_128 bytes, which lead to OOM in my case.