Split commons eclipse pde to remove UI dependency

[dvojtise]

Remove the dependency to the UI of org.eclipse.gemoc.commons.eclipse.pde

Add new org.eclipse.gemoc.commons.eclipse.pde.ui with the moved classes

add pomfirst version of org.eclipse.gemoc.commons.eclipse.pde

move GemocPlugin class from org.eclipse.gemoc.commons.eclipse.pde to org.eclipse.gemoc.commons.eclipse

Companion Pull Requests

• https://github.com/eclipse/gemoc-studio/pull/276
• https://github.com/eclipse/gemoc-studio-modeldebugging/pull/224
• https://github.com/eclipse/gemoc-studio-execution-java/pull/28
• https://github.com/eclipse/gemoc-studio-execution-moccml/pull/70