Closes gh-5028

Introduce dedicate method to determine the actual value to use based on
the configuration and the environment.

Closes gh-1436

* pr/4574:
  Polish contribution
  Support for SendGrid ApiKey

Closes gh-4574

See gh-4574

* pr/4590:
  Polish contribution
  Add Thymeleaf's Java8TimeDialect

Closes gh-4590

Closes gh-4576

Closes gh-4496

Closes gh-5014

Upgrade the `spring-boot-starter-parent` to also filter profile-specific
configuration files.

Closes gh-4856

Closes gh-4598

`server.session-timeout` was deprecated in 1.3 but still used in a sample
that broke once the support for it was removed. This commit fix the build
by using the expected property.

Provides better default for integration tests. Also expand the
documentation of the maven plugin in that area.

Closes gh-4223

Closes gh-1033

Closes gh-3278

* pr/4632:
  Polish contribution
  Remove deprecated use of spring.mvc.*

Closes gh-4632

Closes gh-4086

* pr/4707:
  Polish contribution
  Use a platform-specific line separator

Fix additional use of \n

Closes gh-4707

See gh-4707

* pr/4917:
  Polish contribution
  Remove support for Log4j
  Remove deprecated code

Removing all deprecated code

Closes gh-4905
Closes gh-4917

Apache Log4j 1.x is EOL and has now been replaced by log4j 2. This commit
removes the deprecated support for Log4j 1.x

See gh-4905

See gh-4905

* pr/5013:
  Polish

Closes gh-5013

Closes gh-4955

Since 2.2.5 hasn't yet been released we'll need to rollback for our
release.

See gh-4789

Update the ContextIdApplicationContextInitializer default NAME_PATTERN
to favor the developer defined `${spring.application.name}` value over
the deployer defined `${vcap.application.name}`.

Fixes gh-4926

Update TomcatEmbeddedServletContainerFactory so that logic to disable
persistent sessions happens after Tomcat's standard Manager creation
logic.

Fixes gh-4543

Update `ResourceBundleCondition` to only enable the messages source
if `messages.properties` (and not `messages*.properties`) exists. This
operation is much faster that performing a pattern match since a full
jar entry scan is not required.

Since adding `messages.properties` is good practice and this change
allows us to delete the custom `PathMatchingResourcePatternResolver`
it seems like a fine compromise to make.

Fixes gh-4930
See gh-4811

Closes gh-5003

Closes gh-5002

Closes gh-5001