[LorisInstance] add getModule function

[driusan]

LorisInstance already has functions to check if a module exists, get the module directories, etc.

This adds a getModule to replace \Module::factory() so that the code dealing with modules can be centralized in one place.

[ridz1208]

shouldnt this use getModule() ??

[driusan]

Not sure why this was committed, I think I was just trying to var_dump what got added to debug an exception since the new code is semantically equivalent to the old.. but sure, I can change it to getModule.

[ridz1208]

are you planning on replacing the existing instances of module::factory? otherwise it will never be replaced, we would just be adding another way of doing it

[driusan]

Yes, I'm planning on removing completely removing \Module::factory calls in a different PR. I removed the ones that are in standard LORIS endpoints in the latest commit since they all had access to a LorisInstance object.

When the code is it's moved, it'll use $loris->getModuleDirs() instead of hardcoded paths. So I left the calls in scripts or ajax endpoints which will break since moduleDirs isn't properly set right now and they just use an empty [] directory stub.

I also left the ones that are just using \Module::factory for the side-effect of registering the autoloader. I think when the loading code is moved to getModule() I'll likely decouple the side-effect of the autoloader from the getting (ie. add something like a $module->registerAutoloader() function and it'll help identify the places that need to be updated.