camel-core - Add type converter for string to TimeUnit

Converting to TimeUnit requires special converter as the enum does not allow easy valueOf conversion.

... 43 more
Caused by: java.lang.IllegalArgumentException: No enum constant java.util.concurrent.TimeUnit.MILLISECONDS
at java.base/java.lang.Enum.valueOf(Enum.java:273)
at java.base/java.util.concurrent.TimeUnit.valueOf(TimeUnit.java:75)
at org.apache.camel.converter.DateTimeConverter.toTimeUnit(DateTimeConverter.java:54)
at org.apache.camel.converter.CamelBaseBulkConverterLoader.doConvertTo(CamelBaseBulkConverterLoader.java:495)
at org.apache.camel.converter.CamelBaseBulkConverterLoader.convertTo(CamelBaseBulkConverterLoader.java:58)