Fix Typo in tcp-amqp Sample Config
INTSAMPLES-127 Update Samples to SI 4.0.0

JIRA: https://jira.spring.io/browse/INTSAMPLES-127

Created `maint` branch for ongoing SI 3.0.x samples.
INTSAMPLES-127 Remove Servlet Dependency

travel sample; see INT-3350.
INTSAMPLES-127 Update to SI 4.0.0.RC1