CAMEL-8107: Allow to use property placeholder with default values without having to setup the properties component

Conflicts:
	camel-core/src/main/java/org/apache/camel/component/properties/DefaultPropertiesParser.java
	camel-core/src/main/java/org/apache/camel/impl/DefaultCamelContext.java
CAMEL-8109: Allow to plugin custom functions to property placeholder
CAMEL-8109: Allow to plugin custom functions to property placeholder
CAMEL-8107: Allow to use property placeholder with default values without having to setup the properties component
CAMEL-8107: Fixed merge