Update `JettyEmbeddedServletContainerFactory` to support Jetty 9.4
directly and Jetty 9.3 via reflection. The primary difference between
Jetty 9.3 and 9.4 are the session management classes. Websocket suppport
has also been updates, but this is handled transparently by the
Spring Framework support.

Fixes gh-7599

Update LiveReloadServer so that different synchronization blocks are
used for the sockets and connection lists. Prior to this commit calling
`LiveReloadServer.stop()` would always result in a 60 second delay since
`stop()` owned the monitor add `removeConnection()` (called from a
different thread) needs it to remove the active connection.

Fixes gh-7749

See gh-6543

This commit excludes the transitive dependencies on xml-apis when using
Hibernate. Such dependency is no longer required on modern JDKs

Closes gh-7554

* pr/6900:
  Polish contribution
  Add support for vendor specific Flyway migration locations

Closes gh-6900

This commit adds support for using `{vendor}` placeholder in
`flyway.locations` configuration property value.

See gh-6900

Closes gh-7694

* pr/6613:
  Polish contribution
  Add support for multiple beans in the Flyway and Liquibase endpoints

Closes gh-6613

Closes gh-6610
See gh-6613

Rework cb3d14a3 so that the customizer operates on the Builder rather than
the Cluster. The former exposes many more options.

See gh-7320
Closes gh-7669

* pr/7718:
  Polish @IntegrationComponentScan auto-configuration
  Add @IntegrationComponentScan auto-configuration

See gh-2037
See gh-7718

Update Spring Integration auto-configuration so that
`@IntegrationComponentScan` from `AutoConfigurationPackages` is
implicitly applied. Prior to this commit `@MessagingGateway` interfaces
would only get picked up if `@IntegrationComponentScan` was added
alongside with the `@SpringBootApplication`.

Fixes gh-2037
Closes gh-7718

* pr/7722:
  Polish Spring Integration metrics support
  Refactor Spring Integration metrics support

See gh-7722

Update Spring Integration metrics support since Spring Integration
`4.3.6`+ no longer needs `spring-integration-jmx` enable
`MessageChannel`, `MessageHandler` and `MessageSource` metrics.

- Add `IntegrationManagementConfiguration` conditional auto-configuration
  to provide `@EnableIntegrationManagement` when JMX is `enabled` or there
  is no `IntegrationManagementConfigurer.MANAGEMENT_CONFIGURER_NAME` bean.
  By default this bean doesn't exist and you explicitly should declare it
  (e.g. via `@EnableIntegrationManagement`) if you would like to collect
  metrics. At the same time Spring Integration enables it when JMX
  management is present (that is a purpose of that new
  `IntegrationManagementConfiguration`)

- Change `SpringIntegrationMetricReader` to read metrics from the
  `IntegrationManagementConfigurer`, not `IntegrationMBeanExporter`

- Change `PublicMetricsAutoConfiguration` to register
  `IntegrationManagementConfigurer.MANAGEMENT_CONFIGURER_NAME` bean if
  not present. Since we are here in `actuator`, therefore we are
  interested in the metrics for SI as well.

- Since we don't need JMX for the metrics any more, remove SI-JMX
  dependency from the `spring-boot-starter-integration`.

- Remove `IntegrationManagementConfiguration` modification from the
  `integrationMbeanExporter()`, since that looks like mutation of an
  external object, when end-user would prefer their own options.
  Therefore we don't need `ObjectProvider<IntegrationManagementConfigurer>`, too

- Add missed `MessageSourceMetrics` gathering for the
  `SpringIntegrationMetricReader`

Closes gh-7722

* pr/7723:
  Fix typo in Kafka sample
  Fix compatibility with Apache Kafka 0.10.1

* pr/7714:
  Polish

Update KafkaProperties since  Apache Kafka `0.10.1` changed the type
for the `ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG` from the
`Long` to `Integer`.

Kafka includes the following conversion logic:

    case LONG:
        if (value instanceof Integer)
            return ((Integer) value).longValue();
        if (value instanceof Long)
            return (Long) value;
        else if (value instanceof String)
            return Long.parseLong(trimmed);

So we remain compatible with both `0.10.0` and `0.10.1`

Closes gh-7723

Update the Tomcat logging test to be more like the real scenario.

See gh-7639

Closes gh-7721

Closes gh-7602

Update `SpringBootTestContextCustomizer` to use the full qualified
TestRestTemplate as the registered bean name. Prior to this commit it
was possible that the customizer would replace the relatively common
bean name `testRestTemplate`.

Fixes gh-7711

Update the RelaxedPropertyResolver used to load log properties so that
`${...}` patterns are ignored when possible.

Fixes gh-7719

Closes gh-7710

Closes gh-7707

See gh-7707

See gh-7710

Closes gh-7601