INT-2738 Add Missing `getComponentType()` Methods

JIRA: https://jira.spring.io/browse/INT-2738

Add a `getComponentType()` method for all handlers,
message producers, and message sources that implement
`NamedComponent` (see `SPCA.getComponentType()`).

Add rome as an optional dependency - STS complained
because AtomFeedHttpMessageConverter has a dependency
on it.