Liberty Features to support Spring Boot applications

[tjwatson]

This Epic covers work to support Spring Boot application artifacts (uber/fat JARs) as another supported application type.

The following high-level items will be worked on for this Epic:

1. Add support for a new type of application spring. This support will understand the Spring Boot JAR format and be able to act as the launcher for the Spring Boot application
2. Add support for the embedded server factory to support applications that use spring-boot-starter-web. This includes support for the Spring Boot 1.5 and Spring Boot 2.0 web starter (note the omission of reactive/webflux)
3. Add ability to thin the fat application JAR to allow the lib/ JARs to be separated from the application content. This includes a command line utility as well as automatic thin when deploying FAT jars
4. Add support for the deployer to override server endpoint configuration (e.g http ports) with server.xml settings.

[tjwatson]

This Epic is done now.