Support for container launcher-static configuration

[fryz]

In recent versions of Java, JVM memory configuration has become a bit more sophisticated with supporting launching processes in containers. Specifically, there is a desire to want to utilize some memory configuration flags that only work within containers (eg: MinRAMPercentage/MaxRAMPercentage), but this currently isn't possible with the launcher because it needs to support launching processes not in containers.

It's been proposed to bake some logic into go-java-launcher to detect the CONTAINER=true env var (see gradle-sls-docker's Dockerfile on internal github) and and then flip between a container launcher-static and a regular launcher-static.