Add back default values for the SPDX default model store

[goneall]

See #237 (comment) for discussion.

[goneall]

Since the default model store is in core and the CopyManager and InMemSpdxStore are in the higher level library, we'll probably need to initialize the default model store in the SpdxModelFactory.init().

[dwalluck]

Why wasn't SpdxModelFactory.init() required in V2? I guess I would have to stick this call in a static block in my application somewhere, unless the library itself could initialize it (I assume there's a singleton somewhere).

[dwalluck]

In any case, it would be nice to have init() call DefaultModelStore.initialize(new InMemSpdxStore(), DEFAULT_DOCUMENT_URI, new ModelCopyManager());.

[dwalluck]

Unless it should also be possible for the application to provide a different model store?

[goneall]

Unless it should also be possible for the application to provide a different model store?

How about creating 2 init methods, one that passes in the parameters to DefaultModelStore.initialize and one that just defaults it.

Another complication would be if we called init twice - currently there is no impact on multiple calls. Since we may be changing the state of the DefaultModelStore in the init function, I'm thinking we only modify the state of the DefaultModelStore if it is the initial call to init. Perhaps issue a warning if there is a subsequent call to init that would have modified the model store. A bit more complicated to implement, but it would avoid some common issues.

[goneall]

I'll create a PR with the above proposed solution.

[goneall]

@dwalluck I'm rethinking the second init method with the default model store parameters.

See #286 (comment) for reasoning.