Bump to Eclipse 2022-06

[dvojtise]

Description

Bump Eclipse base version to 2022-06 and its default version of its components and update code to follow API changes.

Bump GEMOC studio version to 3.6.0

Changes

• bump to tycho 2.7.3
• bump to newer version of Melange
• new splash screen
• adapt code to use xtext 2.27, remove some deprecated code, however the studio still include the org.eclipse.xtext.generator feature that is deprecated
• adapt code for use of Sirius 7.0.1
• some improvement in the system tests

Contribution to issues

Contributes to https://github.com/eclipse/gemoc-studio/issues/270

Companion Pull Requests

• PR https://github.com/eclipse/gemoc-studio/pull/273
• PR https://github.com/eclipse/gemoc-studio-modeldebugging/pull/222
• PR https://github.com/eclipse/gemoc-studio-execution-java/pull/27
• PR https://github.com/eclipse/gemoc-studio-execution-moccml/pull/69
• PR https://github.com/eclipse/gemoc-studio-moccml/pull/26