Include the application name on each log line when it is available

Update Logback and Log4J2 so that they include the application name on
each log line. If `spring.application.name` had not been set, or if
`logging.include-application-name` is `false` then the name is not
logged.

Closes gh-35593

spring-boot-project/spring-boot-docs/build.gradle

@@ -293,7 +293,7 @@ task runSpringApplicationExample(type: org.springframework.boot.build.docs.Appli
 task runLoggingFormatExample(type: org.springframework.boot.build.docs.ApplicationRunner) {
 	classpath = configurations.springApplicationExample + sourceSets.main.output
 	mainClass = "org.springframework.boot.docs.features.springapplication.MyApplication"
-	args = ["--spring.main.banner-mode=off", "--server.port=0"]
+	args = ["--spring.main.banner-mode=off", "--server.port=0", "--spring.application.name=myapp"]
 	output = file("$buildDir/example-output/logging-format.txt")
 	expectedLogging = "Started MyApplication in "
 	normalizeTomcatPort()

spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/logging.adoc

@@ -31,6 +31,7 @@ The following items are output:
 * Log Level: `ERROR`, `WARN`, `INFO`, `DEBUG`, or `TRACE`.
 * Process ID.
 * A `---` separator to distinguish the start of actual log messages.
+* Application name: Enclosed in square brackets (logged by default only if configprop:spring.application.name[] is set)
 * Thread name: Enclosed in square brackets (may be truncated for console output).
 * Correlation ID: If tracing is enabled (not shown in the sample above)
 * Logger name: This is usually the source class name (often abbreviated).
@@ -39,6 +40,7 @@ The following items are output:
 NOTE: Logback does not have a `FATAL` level.
 It is mapped to `ERROR`.
 
+TIP: If you have a configprop:spring.application.name[] property but don't want it logged you can set configprop:logging.include-application-name[] to `false`.
 
 
 [[features.logging.console-output]]