Move to Maven/Tycho for projects and build infrastructure

[LorenzoBettini]

Replaces #500

[cdietrich]

yes. the same as it would be a monorepo. the only place we use other version is xtend-maven-plugin.
and it should be done with profile so that it can be decided if from sonatype or from upstream branches

[LorenzoBettini]

yes. the same as it would be a monorepo. the only place we use other version is xtend-maven-plugin. and it should be done with profile so that it can be decided if from sonatype or from upstream branches

I'm doing some experiments in xtext-core concerning the versioning across Git repositories.

So I introduced xtext-dev-bom-version that defaults to project.version and can be redefined in projects like xtext.logging that has a different version eclipse/xtext-core@e329fc2

Besides that, I always use project.version for referring to xtext artifacts coming from other git repositories: eclipse/xtext-core@31358b5

During building, we use the profile useJenkinsSnapshots so the snapshots are found. But what about without that profile? For example, in Eclipse? Without snapshot repository specification, snapshots are not found. A profile for sonatype snapshots will not work because activeByDefault, as I said in the past, is not really active by default.

Thus, the sonatype snapshot repository is the default (specified outside profiles), and the profile useJenkinsSnapshots explicitly disables that sonatype snapshots repository: eclipse/xtext-core@53f0781

[cdietrich]

with the repo merge done this is obsolete