Draft: purge tools and platform-tools
This purges the Android SDK packages tools and platform-tools from the buildserver image. ant builds still need tools v25.5.2 for the android update
command, but that can now be easily handled in the build metadata:
sudo:
- sdkmanager "tools;25.5.2"
Other than that, it should be very rare that an app build needs anything from tools or platform-tools. sdkmanager is also part of tools, but we're using the pre-installed fdroid/sdkmanager now.