Android build pipeline steps

What

• Come up with Jenkins pipeline matching EXISTING BF functionality for Android builds

Why

• We want to build Android apps with Jenkins pipelines!

How

• Do check out from SCM
• Ignore Ant builds for now, only focus on Gradle. Gradle wrapper will be in the build container already (part of some other task)
• Latest Android SDK is a MUST, as that's the key value of a hosted build farm - especially since Google does lot's of releases during the year
• No Jenkins plugin creation for missing stuff yet. See RHMAP-11796 for that.
• A debug keystore is required for signing binaries. Allowing clients to pass keys is to be done in a separate task. For a devl person, debug keystore is necessary to install on a device