Closes gh-20045

Closes gh-20167

Closes gh-20166

Closes gh-20165

Closes gh-20164

Closes gh-20163

Closes gh-20162

Closes gh-20161

Closes gh-20092

Previously, dependency management for JNA was provided by
spring-boot-dependencies so it affected users' applications. It was
original added for Elasticsearch but is no longer needed for that
purpose. We use JNA in spring-boot-buildpack-platform which is used
by our Gradle and Maven plugins and should not affect an application's
use of JNA.

This commit moves management of JNA from spring-boot-dependencies into
spring-boot-parent. This means that users' applications will now be
free to use whatever version of JNA meets their needs while still
controlling the version used for image building via Gradle or Maven.

Closes gh-20156

Closes gh-20160

Closes gh-20159

Previously, the configprop macro was being used in the source but the
extension that implements the macro was not available to Asciidoctor.
This led to the references not being checked at build time and the
macro being left as-is in the rendered documentation.

This commit updates the dependencies that are available to Asciidoctor
to include the extension and the projects which define the
configuration properties referenced in the documentation.

Closes gh-20149

Closes gh-20158

* gh-19953:
  Upgrade to Asciidoctor Gradle JVM 3.0.0

Closes gh-19953

See gh-19953

* pr/20157:
  Upgrade CI to Docker 19.03.5

Closes gh-20157

See gh-20157

Closes gh-20155

Closes gh-20154

* pr/20143:
  Fix Spring Boot version reference in spring-boot-starter-parent

Closes gh-20143

See gh-20143

Closes gh-20104

Closes gh-20105

Closes gh-20107

This commit fixes the `Created` date and time of the ephemeral builder
container image at the Windows epoch plus one second
(1980-01-01T00:00:01Z). This date matches the created date of the builder
image and influences the created date of the resulting image. Using
a fixed date for images ensures that the digest is consistent for all
images with the same version.

Fixes gh-20126

This commit adds a `createdBy` structure to the metadata of the ephemeral
builder container image that identifies Spring Boot as the creator of the
image, along with the Spring Boot version.

See gh-20126

Prior to this commit, Actuator endpoints would use the application
ObjectMapper instance for serializing payloads as JSON. This was
problematic in several cases:

* application-specific configuration would change the actuator endpoint
output.
* choosing a different JSON mapper implementation in the application
would break completely some endpoints.

Spring Boot Actuator already has a hard dependency on Jackson, and this
commit uses that fact to configure a shared `ObjectMapper` instance that
will be used by the Actuator infrastructure consistently, without
polluting the application context.

This `ObjectMapper` is used in Actuator for:

* JMX endpoints
* Spring MVC endpoints with an HTTP message converter
* Spring WebFlux endpoints with an `Encoder`
* Jersey endpoints with a `ContextResolver<ObjectMapper>`

For all web endpoints, this configuration is limited to the
actuator-specific media types such as
`"application/vnd.spring-boot.actuator.v3+json"`.

Fixes gh-12951

Closes gh-20148

Closes gh-19953

Closes gh-20103

Closes gh-20142

* pr/20141:
  Exclude jcl-over-slf4j also on Reactive Cassandra starter

Closes gh-20141

See gh-20141

Closes gh-20064