To be compatible with Gradle's plugin portal, plugins must have an
ID that uses a reverse domain name. This means that spring-boot is
not compatible.

This commit introduces a new ID, org.springframework.boot, and
deprecates the old ID.

Closes gh-6997

Closes gh-6787

* pr/6367:
  Polish contribution
  "spring war" should copy resources to WEB-INF/classes

Closes gh-6367

Closes gh-6351

Closes gh-6825

The cache abstraction is a core feature of the Spring Framework. Basic
features such as `@EnableCaching` are therefore available by default with
no extra dependencies necessary.

However, the actual cache adapters for JCache, Ehcache 2.x, Caffeine and
Guava are located in a separated module, `spring-context-support`. Spring
Boot provides that artifact via the `spring-boot-starter-cache` starter.

It is quite easy to "only" add the cache library dependencies and forget
about this extra dependencies since `@EnableCaching` is available by
default. This commit clarifies the role of the starer in each section so
that it is more obvious. We're already explaining this at the beginning
of the section but it seems that's not enough.

Closes gh-7071

* pr/7073:
  Upgrade to Spring Integration 4.2.11

Closes gh-7073

# Conflicts:
#	spring-boot-dependencies/pom.xml

* pr/7074:
  Upgrade to Spring Integration 4.3.4, AMQP 1.6.3

Closes gh-7074

* pr/7085:
  Fix a typo

Closes gh-7085

* pr/7089:
  Fix NoClassDefFoundError when Mockito is missing

Update MockReset class to check for the presence of the MockUtil class
before attempting to use it.

Fixes gh-7065

Closes gh-7040

Closes gh-6986

Previously, an URI and individual client attributes can be set to
configure the mongo client. In such a scenario, the URI is ignored.

This commit changes the URI to be "null" and the creation of the client
to fail if both the uri and client attributes are set. If no client
attributes are set, the uri is used as before.

Closes gh-6739

Closes gh-6978

# Conflicts:
#	spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/ManagementServerProperties.java
#	spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/ManagementServerPropertiesAutoConfigurationTests.java

Closes gh-7068

* pr/7081:
  Polish

Closes gh-7081