Remove (now) obsolete equinox.launcher.releng and osgi.companion project

[HannesWell]

Some of the ANT tasks in o.e.equinox.launcher.releng/build.xml where used in the old launcher building jobs, which are now obsolete as well since Equinox builds the launcher binaries in its Jenkins pipeline.

All other tasks seem to be out-dated for much longer.

@tjwatson or @sravanlakkimsetti or did I oversee still relevant use-cases of these tasks?
Tom you added the org.eclipse.equinox.osgi.companion project about a decade ago as part of Bug 363246. But since o.e.osgi.services is now effectively empty (#18) I assume that it is not relevant anymore, is it?

[github-actions]

Test Results

  660 files  ±0    660 suites  ±0   1h 9m 38s ⏱️ - 4m 41s
2 195 tests ±0  2 148 ✅ ±0   47 💤 ±0  0 ❌ ±0 
6 729 runs  ±0  6 586 ✅ ±0  143 💤 ±0  0 ❌ ±0 

Results for commit 43cad6d. ± Comparison against base commit 1b7612a.

♻️ This comment has been updated with latest results.

[HannesWell]

@tjwatson or @sravanlakkimsetti any objections about removing these projects?

[tjwatson]

@tjwatson or @sravanlakkimsetti any objections about removing these projects?

If they are no longer used then it is only confusing to keep them around.

[sravanlakkimsetti]

@tjwatson or @sravanlakkimsetti any objections about removing these projects?

If they are not used. please go ahead and remove them

[HannesWell]

I didn't found any reference to it in the entire SDK/aggregator (plus submodules) and the pipelines/workflows to build everything in this repository is defined as code here now, so I don't know of any relevant usage.

The only task for which it might be used is building one of the contributed linux s390 executables in https://github.com/eclipse-equinox/equinox.binaries/tree/af72d120b237ca99ff37c345e9d0ec20ed49f48a/org.eclipse.equinox.executable/contributed/gtk/linux
But I don't know if they are still used and if one can just call the build scripts directly as it is done in the Jenkins-pipeline for all other executables as well:

equinox/Jenkinsfile

Lines 212 to 220 in bb4e748

	withEnv(["JAVA_HOME=${WORKSPACE}/jdk.resources", "EXE_OUTPUT_DIR=${WORKSPACE}/libs", "LIB_OUTPUT_DIR=${WORKSPACE}/libs"]) {
	dir(ws) {
	if (isUnix()) {
	sh "sh build.sh -ws ${ws} -os ${os} -arch ${arch} install"
	} else {
	bat "cmd /c build.bat -ws ${ws} -os ${os} -arch ${arch} install"
	}
	}
	}