Support option to not fork HSQL or Tomcat Processes

[mrapczynski]

Is your feature request related to a problem? Please describe.
No, not a problem. I am using Docker to package pre-built developer environments. The embedded HSQL database or Tomcat spawn independent child processes, and this presents unique challenges when trying to do process coordination within a Docker container. The default spawn: true is fine for most situations, but there are circumstances when it would be nice to override this.

To sum it up: define an option for the HSQL or Tomcat tasks to create foreground processes while retaining the existing conveniences of the Gradle task config.

Describe the solution you'd like
Replace spawn: true for the hsqlStart and tomcatStart tasks with (project.findProperty('antNoSpawn') == 'true') ? false : true

Describe alternatives you've considered
Hacky Bash scripting inside the containers. It can work, but emphasis on how hacky it is.

Additional context
Allowing the Gradle tasks to create foreground processes would allow easier process coordination with tools such as Supervisord or Monit (inside or outside of a container environment).

Tested with the following scenarios:

1. ./gradlew --console=plain -PantNoSpawn=true hsqlStart and
2. ./gradlew --console=plain hsqlStart

[drewwills]

👍 This sounds like a good idea.