Ability to read Micronaut configuration from Application preferences directory

[msgilligan]

Desktop applications often have configuration/data/preferences directories in well known locations. For example an application named "Application" might have the following platform-specific configuration directories:

macOS: ~/Library/Application Support/Application or perhaps ~/Library/Preferences/Application
Linux: ~/.application
Windows: …

It would nice to be able to read Micronaut configuration files (in .properties, .json, .yml formats. And for Groovy users .groovy) using the Micronaut PropertySourceLoader mechanism from these locations.

See https://docs.micronaut.io/1.3.3/guide/index.html#propertySource for information on PropertySourceLoader s.