birch: store captured status records as machine readable json with machine times

[yarikoptic]

ATM only some ad-hoc timing as

pi@Birch-4115966:/mnt/td $ grep -6  '916.794940 0f8' 20231031-155059
-921.192816 1f0 2
-921.172816 0f0 1
-919.192776 1f0 2
-919.172776 0f0 1
-917.192796 1f0 2
-917.172791 0f0 1
-916.794940 0f8 0
-916.524089 0f0 1
-915.192751 1f0 2
-915.172776 0f0 1
-913.192771 1f0 2
-913.172766 0f0 1
-911.192761 1f0 2

and those times are not absolute times, they cycle etc.

format is somewhere on the wiki -- yet to find exact address https://wiki.curdes.com/bin/view/CdiDocs/BirchUsersManual

TODO here: decide on schema of the record