Add history expire option.

[gary-ruizhang]

Auto clean command history which timestamp older than a config option. Currently I use the following sql to delete command history older than three months.

delete from history where timestamp < unixepoch('now', '-3 month') * 1000000000;

[ellie]

Hey! We could look into getting this sorted, just please be aware that by running that SQL history sync will not work for you. Deletion has to go through Atuin's delete interface