Add read-only "derived" property to NavigationCase

I think Dan is talking about the NavigationCase Java language artifact.

DA> The problem is, there is no way to know whether that NavigationCase
DA> was sourced from a real navigation case or derived using implicit
DA> navigation. So what I am looking for is the following API addition:

DA> NavigationCase#isDerived()

DA> I suggest "derived" over "implicit" because it leaves room for any
DA> sort of dynamic creation...perhaps implicit isn't the only option.

I like that. I'll look into how implementable it is.
#### Environment
Operating System: All
Platform: All
#### Affected Versions
[2.0]

Start by locating the NavigationCase Java artifact and tracing how navigation cases are sourced versus derived through implicit navigation. The work is done when a read-only isDerived() API is available and distinguishes real navigation cases from derived ones; no specific test or file is named in the issue.

Written by the indexing model from the issue text.