v0.13

Changes:

- drop privileges when running node exporter
- update node exporter to 1.7.0
- add node exporter to osx packages
- add check_load plugin
- improve docs and help pages
- add folder size support to check_files (#38)
- add basic promethes metrics
- check_eventlog: finish implementing
- fix reading empty config files (#58)
- fix packaging for debian <= 12