[I/Y-Build] Unify and streamline build and naming of products

[HannesWell]

Build OSGi Starter Kit for all supported platforms.
FYI @tjwatson and @laeubi (but I assume almost nobody really cares).

Unify names of Eclipse products built for Windows, i.e. use the same <ws>-<os>-<arch> naming schema like for Linux and macOS, even though ws and os segments are the same.
I assume nobody really cares about the exact names either (except that existing scripts would not require special handling for Windows anymore).
We just have to adjust the api-tools generation after next release at

• eclipse.platform.releng.aggregator/eclipse-platform-parent/pom.xml

  Lines 557 to 559 in 8210d25

  	<arg>-DpreviousBaseURL=https://download.eclipse.org/eclipse/downloads/drops4/${previousReleaseId}/eclipse-SDK-${previousReleaseVer}-win32-x86_64.zip</arg>
  	<arg>-DpreviousBaselineName=Eclipse-SDK-${previousReleaseVer}</arg>
  	<arg>-DpreviousBaselineFilename=eclipse-SDK-${previousReleaseVer}-win32-x86_64.zip</arg>

• eclipse.platform.releng.aggregator/eclipse.platform.releng.tychoeclipsebuilder/eclipse/buildScripts/api-tools-builder.xml

  Line 187 in 8210d25

  value="${buildDirectory}/eclipse-SDK-${buildLabel}-win32-x86_64.zip" />

if it's then still using the Eclipse SDK product for Windows only (I hope not).