[keycloak-dev] Admin recovery update

The hope was to use the new offline CLI mode to add reset admin password and import/export operations. However, it turns out to be a bit of a pain in the ass to do so. For now we'll just have a system property that is used to reset admin pass, similar to how import/export works. Hopefully soon we can improve on this and use the offline CLI mode, or alternatively create a custom script that does this. The main issue with these is datasources are not available.