AMQP-406: Add RoutingCF to the RabbitTemplate

JIRA: https://jira.spring.io/browse/AMQP-406

* Add support of `connection-factory-selector-expression` for the `RabbitTemplate`
and provide logic to bind target `ConnectionFactory` to the invocation context based on the result of the expression evaluation.

AMQP-406: Fix double ThreadLocal resource

Polishing

AMQP-406: introduce `receiveConnectionFactorySelectorExpression`

Doc Polishing
AMQP-428: Add Logback `AmqpAppender`

JIRA: https://jira.spring.io/browse/AMQP-433, https://jira.spring.io/browse/AMQP-428

Fix `amqp.rabbit.log4j.AmqpAppender` JavaDoc typo

Polishing

Add category abbreviation [o.s.a.r.l.AmqpAppenderIntegrationTests].

Retain full category in AMQP headers.