Replace `ObjectMapper.getRegisteredModuleIds()` (2.x) with `ObjectMapper.getRegisteredModules()` (3.0)

[cowtowncoder]

(note: this is retro-active issue for change already made in 3.0, included in 3.0.0-rc1 -- but with signature change in 3.0.0-rc9)

Due to changes in registration of Jackson Modules (Module in 2.x, JacksonModule in 3.x), it is now possible to get access to actual modules added/registered, and not just ids.
So it makes sense to change accessor as well.

One note: while 3.0.0-rc1 - 3.0.0-rc8 had replacement as

public Collection<JacksonModule> getRegisteredModules();

we will change this further in 3.0.0-rc9 to

public Stream<JacksonModule> getRegisteredModules()

for more modern style and to avoid any chance of accidental mutability.