Spring Boot ATNA support

ipf-atna-spring-boot-starter sets up the infrastructure for ATNA auditing.

The dependency on the IPF Spring Boot ATNA starter module is:

    <dependency>
        <groupId>org.openehealth.ipf.boot</groupId>
        <artifactId>ipf-atna-spring-boot-starter</artifactId>
    </dependency>

All IHE-related Spring boot starter modules depend on this starter module, so if you use one of those you do not have to explicitly depend on ipf-atna-spring-boot-starter.

As of IPF 3.7, ipf-atna-spring-boot-starter does not depend on ipf-spring-boot-starter anymore. This makes it usable in scenarios where no other IPF modules are used and does not drag in 3rd party dependencies like Apache Camel or Groovy anymore.

ipf-atna-spring-boot-starter auto-configures by default:

a configurable AuditContext bean
a basic listeners that write ATNA audit events upon application startup and shutdown (ApplicationStartEventListener and ApplicationStopEventListener)
a basic listener for login events if Spring Security is on the classpath (AuthenticationListener)

You can define your own @Beans of this type in order to override the defaults.

ipf-atna-spring-boot-starter provides the following application properties that configures the AuditContext as described here.

Property (`ipf.atna.`)	Default	Description
`audit-enabled`	false	Whether auditing is enabled
`audit-repository-host`	localhost	Host of the ATNA repository to send the events to
`audit-repository-port`	514	Port of the ATNA repository to send the events to
`audit-repository-transport`	UDP	Wire transport format (UDP, TLS)
`audit-source-id`	`${spring.application.name}`	Source ID for ATNA events
`audit-enterprise-site-id`		Enterprise Site ID for ATNA events
`include-participants-from-response`	false	Whether to include (patient) participants from responses as well
`audit-source-type`	4 (ApplicationServerProcess)	Type of Audit Source
`audit-queue-class`	`org.openehealth.ipf.commons.audit.queue.SynchronousAuditMessageQueue`	Queue implementation for auditing
`audit-sender-class`	as indicated by `audit-repository-transport`	ATNA sender implementation
`audit-exception-handler-class`	`org.openehealth.ipf.commons.audit.handler.LoggingAuditExceptionHandler`	Exception handler impleemntation
`audit-value-if-missing`	`UNKNOWN`	Value used for mandatory audit attributes that are not set

As of IPF 3.7, you can also provide your own @Beans returning an instance of AuditMessageQueue, AuditMessagePostProcessor, AuditTransmissionProtocol, AuditMetadataProvider, AuditExceptionHandler and TlsParameters.