Support for multi-module projects

[yeekangc]

Complete support for multi-module projects in Liberty Tools for Eclipse IDE.

• Support Maven multi-module dev mode with only 1 "server module" even with >1 module with no downstream modules ci.maven#1606
• Model aggregator/aggregated relationship among Maven projects within an Eclipse workspace #489
• Provide tree-based view reflecting aggregator/aggregated relationship for Maven modules #490
• Provide multi-module-aware Run/Debug Configuration with appropriate defaults, and caching of custom-selected values. #491
• Broaden detection of "is this a Liberty project?" calculation #492
• Allow for execution of Run Config from non-Liberty projects, not just the current Liberty project #493
• For multi-module Maven cases, provide for execution of tests and viewing of test reports #494
• Consider devc for multi-module Maven cases. Is there anything we should do related to detecting where the Dockerfile lives? #495
• Multi-mod Maven case doesn't allow launch from "child" directory using mvnw wrapper from parent  #347

A mock set of screenshots summarizing some of this in a quick set of views: