Make a context project optional for EclipseRunMojo

[HannesWell]

This might be useful if one wants to run Eclipse from Maven without a context project.

[github-actions[bot]]

Test Results

1 008 files  1 008 suites   4h 50m 48s ⏱️ 1 293 tests 1 272 ✅ 20 💤 1 ❌ 3 879 runs  3 813 ✅ 64 💤 2 ❌

For more details on these failures, see this check.

Results for commit b20967d7.

:recycle: This comment has been updated with latest results.

[HannesWell]

I did now make some experiments and there is indeed an empty project injected if no pom is available, but its basedir is null. So I adjusted that. But this experiment also showed that it doesn't work that simply as one has to define a (p2-) repository to resolve the artifacts building the runtime. And as a repository is a complex type, I'm not aware of a way to define it on the CLI, or do you know one?

[laeubi]

What cam into my mind is to define an additional parameter (e.g. repo-url) that can be used as a fallback for CLI invocation, we can then use an ID as eclipse-run-cli for example so users can still configure that.