INTSAMPLES-121: Upgrade to SI 3.0 and SPR 3.2.6

JIRA: https://jira.springsource.org/browse/INTSAMPLES-121
Enable Intermediate modules

Ignore MS & Oracle tests
INTSAMPLES-125/126:SF 3.2.7, SI 3.0.1; Schemas

JIRA: https://jira.springsource.org/browse/INTSAMPLES-125

Polishing some poms and enable all modules

INTSAMPLES-126: Fix XSD versions vulnerability

JIRA: https://jira.springsource.org/browse/INTSAMPLES-126

Polishing

Add dummy JUnit to monitoring "test".
Change Maven Repos to spring.io
INTSAMPLES-128 Update SI to 3.0.2, SF to 3.2.8
Fix Typo in tcp-amqp Sample Config
INTSAMPLES-127 Polishing

- PR Comments
- Switch to Jackson2
- Fix oxm config

Polishing

INTSAMPLES-127 Update to SI 4.0.0.RC1

INTSAMPLES-127 Remove Servlet Dependency

travel sample; see INT-3350.

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-122: Migrate to Gradle

JIRA: https://jira.springsource.org/browse/INTSAMPLES-122