Download appoptics-agent JAR file with all dependencies

The AppOptics Java instrumentation agent jar file. This artifact provides a convenient way to download the agent jar from public Maven repository. Please take note that this should NOT be included as a part of the project dependencies. Rather, this artifact should be integrated into the build process by using extra step such as the "copy" goal of "maven-dependency-plugin". For more information, please refer to https://docs.appoptics.com/kb/apm_tracing/java/install/#getting-the-agent-jar