fix: loglevel in custom log4j2.xml overriden by loggingLevel config

[iromli]

The cloud-native setup uses custom log4j2.xml (specified via Java system property -Dlog4j2.configurationFile) to add prefixes, customizable log levels and outputs, however oxcore's LoggerService overrides the log level that set via custom log4j2.xml. For example, given certain logger is set to TRACE, the LoggerService reads the loggingLevel config from persistence instead, thus replacing the desired log level. Some ox components, e.g. oxAuth and Fido2, has support for externalLoggerConfiguration, but the rest of the components don't have similar config.