Add method to ResourceResolver to retrieve a directory

Task List

• Steps to reproduce provided
• Stacktrace (if present) provided
• Example that reproduces the problem uploaded to Github
• Full description of the issue provided (see below)

Steps to Reproduce

1. Create a file somefile.txt in src/main/resources/somedir.
2. Inject the ResourceResolver.
3. Call resourceResolver.getResource("classpath:somedir/")--> this returns Optional.empty but reference to directory expected.

Note that getting the somefile.txt resource directly via resourceResolver.getResource("classpath:somedir/somefile.txt") dies return the resource.

My current alternative is val dir = MyClass::class.java.getResource("/somedir/").

Expected Behaviour

ResourceResolver.getResource should return URI pointing to directory.

Actual Behaviour

Optional.empty returned.

Environment Information

• Operating System: OSX
• Micronaut Version: 1.0.1
• JDK Version: JDK8 (Kotlin)