This commits adds a slice test infrastructure for MongoDB, similar to
what `@DataJpaTest` does with JPA.

By default, an embedded Mongod process is used if available.

See gh-7600

This commit improves the logic of the embedded Mongo support to use a
random port if no custom port has been specified. This doesn't change
the default if the embedded support isn't active.

Closes gh-8044

Previously, the actuator's endpoints produced application/json and,
where appropriate, also consumed application/json. Without a custom,
versioned media type, it's impossible for us to make changes to the
endpoints without breaking clients.

This commit introduces a new media type,
application/spring-boot.actuator.v1+json, that is now produced by
default with application/json also being produced if requested.
Endpoints that consume JSON will now also accept content the uses
the new media type in addition to application/json.

Closes gh-7967

* pr/8039:
  Indenting SpringApplication javadoc code

Closes gh-8039

Closes gh-8040

* pr/8038:
  Upgrade to Spring AMQP 1.7.0.RELEASE

Closes gh-8038

Closes gh-8033

Closes gh-7974

Fixes gh-7091

Closes gh-7862

Previously, when the ExpectedException JUnit rule was used with
FilteredClassPathRunner a LinkageError would occur if any of
ExpectedException's methods that take a Hamcrest Matcher were called.
This was due to the FilteredClassLoader delegating loading of
org.junit classes to its parent but not org.hamcrest classes. This
resulted in JUnit classes loading one version of the Hamcrest class
and the test class loading another.

This commit ensures that both the JUnit classes and the test class
use the same version of Hamcrest classes by also delegating the
loading of org.hamcrest classes to FilteredClassLoader's parent.

* pr/8030:
  Fix closing parentheses

Closes gh-8030

By default, `@DataJpaTest` (and `@AutoConfigureTestDatabase`) attempt to
replace any existing `DataSource` by an embedded one. Previously, if
there is was no embedded database on the classpath, the exception message
did not provide that context in the error message.

This commit clarifies the error message to conduct
`TestDatabaseAutoConfiguration` (that is replacing the existing
`DataSource`).

Closes gh-7797

* gh-7990:
  Polish "Avoid property name collisions when serializing AuditEvent to JSON"
  Avoid property name collisions when serializing AuditEvent to JSON

See gh-7990

Previously, in case the data for the audit event contained an entry
with the key "type", the member `type` from the AuditEvent would be
overwritten when rendering to JSON due to the use of @JsonAnyGetter on
the data property.

This commit removes @JsonAnyGetter so that the data map is rendered as
a separate property in the JSON.

Closes gh-7990

Closes gh-8025

Previously, SpringBootApplication relied on implicity aliasing of
exclude and excludeName that worked because the two attributes have
the same names as the equivalent attributes on
EnableAutoConfiguration.

This commit updates SpringBootApplication to make the aliases explicit
and also adds tests to EnableAutoConfigurationImportSelectorTests to
verify that the aliasing is working as intended.

Closes gh-7951

This commits adds manual metadata for enums that have a default value
since the annotation processor is not able to detect that yet.

Closes gh-7890

Previously, TestRestTemplate would only apply the UriTemplateHandler
to Strings and not to URIs. When using the auto-configured
TestRestTemplate, this prevented relative URIs from being
made absolute using LocalHostUriTemplateHandler.

The commit updates TestRestTemplate to turn URIs into Strings before
passing them to the delegate RestTemplate. Turning them into Strings
ensures that the delegate calls the UriTemplateHandler.

Closes gh-7891

Previously, when DevTools' was used it would set the application
context's ResourceLoader and overwrite any custom ResourceLoader that
had been configured. On the rare occasion when the user had customized
the ResourceLoader this meant that the customization was lost and
certain resources would become unavailable.

This commit updates DevTools' ResourceLoader to delegate a custom
ResourceLoader if one has been configured. If one has not been
configured it delegates as before, i.e. to
WebApplicationContextResourceLoader for web applications and to
DefaultResourceLoader for all others apps.

Closes gh-8010

Update `ConfigurationPropertiesBindingPostProcessor` so that
`@Validated` is expected to be used to trigger JSR-330 validation.

Any existing configuration classes that use JSR-330 annotations but
don't have `@Validated` will currently still be validated, but will
now log a warning. This should give users a chance to add the requested
annotations before the next Spring Boot release where we will use them
as the exclusive signal that validation is required.

Closes gh-7579

Replace JSR-330 validation annotations from all internal
`@ConfigurationProperties` classes with standard Asserts.

Prior to this commit validation of our own configuration properties
would only occur when the user happens to have compliant JSR-330
implementation on their classpath.

See gh-7579