INT-3101 Allow PPC for 'durable' in GF CQ Adapter

JIRA: https://jira.spring.io/browse/INT-3101

Change schema type from xsd:boolean to union with string and boolean.
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.
INT-3338: MongoMS: Add `priority` and `sequence`

JIRA: https://jira.spring.io/browse/INT-3338

INT-3338: Add Docs

INT-3338: Make `priority` 'smart'

Add `Sort` for all group queries dependently of `priorityEnabled`.
Avoids the need to configure separate collections for different type of `MessageStore`

INT-3338: Add `MongoDbChannelMessageStore`

INT-3338: Polishing, Fixes, Improvements

Doc Polishing

Fix stream test.