Updating task metrics to micrometer 1.10

Changes include:
* Use Observable instead of metrics
* Update the setting of lowCardinalityTag to the correct events.
* Update the docs
* Remove EXTERNAL_EXECUTION_ID
* Utilize registry provided by boot instead of globalregistry
* Set the handler until Boot does this as shown on line 80 of TaskLifecycleConfiguration.
* Uses Observability long task timer

Updated to latest changes in Micrometer Observability

Updated based on code review and api change

Finished removing the metrics registry

Updated based on code review

Readded cloud foundry keys to observations

Renamed metrics to observations where applicable

Updated metric sample to be observation sample

Updated to set defaults and migrate tests to infrastructure

Updated based on code review

Remove duplicate keyvalues from task observation

Added DocumentedObservation to create the observation
Migrated code to use the LowerCardinality KeyNames from the DocumentedObservation
Test cleanup
Updated code based on code review

Exception is handled by the error in the observation vs logging it as a task metric key value

Updated to use ObservationConvention

Updated to handle user defined convention vs default

Removed the snapshot versions of observations

Removed unnecessary dependencies

Checkpoint tests fail after re-adding 1.10-SNAPSHOT

Replaced TimeObservationHandler with DefaultMeterObservationHandler

Updated to set micrometer to latest milestone

Updated to rename TaskValuesProvider variables to ObservationConvention

spring-cloud-task-samples/task-observations/src/test/java/io/spring/taskobservations/TaskObservationsApplicationTests.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2022-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.spring.taskobservations;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.system.CapturedOutput;
+import org.springframework.boot.test.system.OutputCaptureExtension;
+
+import static org.assertj.core.api.AssertionsForInterfaceTypes.assertThat;
+
+@SpringBootTest
+@ExtendWith(OutputCaptureExtension.class)
+class TaskObservationsApplicationTests {
+
+	@Test
+	void contextLoads(CapturedOutput output) {
+		String result = output.getAll();
+		assertThat(result).contains("spring.cloud.task(TIMER)[application='task-observations-application-58', " +
+			"error='none', service='task-observations-application', " +
+			"spring.cloud.task.execution.id='1', spring.cloud.task.exit.code='0', " +
+			"spring.cloud.task.external.execution.id='unknown', spring.cloud.task.name='taskmetrics', " +
+			"spring.cloud.task.parent.execution.id='unknown', spring.cloud.task.status='success']; " +
+			"count=1.0, total_time=");
+	}
+
+}