plugininstall.pl: Save plugindb change state in $lbstmpfslogdir/plugins_state.json
plugininstall.pl: Save plugindb change state in $lbstmpfslogdir/plugins_state.json

- $plugins_state.json saves epoch timestamp of install, update, uninstall
- Used as change detection for plugin database (new plugin installed, plugin removed...)
- Reduced lock time on uninstall

mschlenstedt/Loxberry,mschlenstedt/Loxberry,mschlenstedt/Loxberry,mschlenstedt/Loxberry,mschlenstedt/Loxberry,mschlenstedt/Loxberry