another update of Wiki docs for existing Android xMake release build

-We currently release the Android apps off a branch called ``android-xmake-release`` and referred to in the sequel as the "Android release branch."

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-The Android release branch holds the changes required to run a successful Android build in xMake. The actual build is still the Gradle build that xMake invokes like this:

-In order to get the Android release branch merged into the ``rel-x.y`` branch, the same process as explained above for the merge of iOS branches into ``fa/rel-x.y`` is required. In particular, this means that a Java Correction Workbench Correction Request [needs to be created](https://css.wdf.sap.corp/sap/bc/bsp/spn/jcwb/default.htm?newCMForProject=sapsailingcapture&newCMComponentName=SV-COE-MSO-CDP) and the latest commit to be pushed to ``refs/for/rel-x.y`` needs to be amended so that it contains a valid ``Change-Id:`` and ``CR-Id:`` line. Then, the commit needs to be voted on. Other than for the MiOS branches under ``fa/rel-x.y`` it seems to be required that _another_ committer votes with +2 to enable a merge. Once this has been done, the blue ``Submit`` button will appear on your change page (something like [https://git.wdf.sap.corp/#/c/1436212/](https://git.wdf.sap.corp/#/c/1436212/)) that you can use to technically get the commit merged into the ``rel-x.y`` branch.

-This will checkout the `android-xmake-release` branch, merge the `fa/arel-1.4` release branch into it, push the result again so Gerrit knows this commit / change already. Then, the version substitutions for all `pom.xml` and `MANIFEST.MF` files are carried out automatically by looking at the version currently declared in the root `pom.xml`. If that's a `-SNAPSHOT` version, only the `-SNAPSHOT` suffix is removed to obtain the new release version number. If no `-SNAPSHOT` suffix is found, the micro version is increased by one (e.g., 1.4.18 --> 1.4.19). Furthermore, the `android:versionCode` number is increased by one for each of the three apps in their `AndroidManifest.xml`, and the `android:versionName` which is assumed to have the format major.minor will have the minor version increased by one. The result is committed to git and the resulting commit is pushed to the fa/rel-1.4 branch.

-Once this is done, a [Customer release build can be started](https://xmake-mobile-dev.wdf.sap.corp/job/sapsailingprogram/job/sapsailingcapture.android-SP-REL-common_directshipment/). Select "Build with Parameters" from the left, then select ``Stage`` as the build mode, then ``customer`` as the ``RELEASE_MODE`` and enter the ``fa/rel-x.y`` branch name in the "TREEISH" field, make sure the Maven version 3.1.1 is selected, select Tycho version 1.0.0, switch the "Next development version" to ``no change`` and click the "Build" button. If the build succeeds, Final Assembly should be able to _promote_ the build artifact, such as the ``.apk`` files which should have been signed using the SAP certificate.

-## Backend Build vs Android Build

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-Due to some incompatibilities of the Android Build with specifics of the Tycho Build, it's not possible to build the backend and Android apps in one execution. That's why there are several profiles that control, what is part of the specific build.

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-The default activation of the profiles causes the backend build to run. The relevant profiles to switch between backend and Android build are:

-* with-mobile (defauts to off)

-* with-not-android-relevant (defauts to on)

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-So to run the Android apps build you have to add "-P -with-not-android-relevant -P with-mobile" to the Maven command line.

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-There are several differences when running the build on Lean DI. Due to this, it's necessary to implement some changes in the build. To realize the build for Lean DI there is a specific branch "android-xmake-release". It is intended that most of the Lean DI specific logic is implemented on "master" in specific Maven profiles. This causes the release branch to only have few differences compared to "master". The most notable differences are:

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-* Configuration of parent POM "com.sap.ldi:ldi-parent" in workspace POM

-* Versions are set to not be *-SNAPSHOT but release versions

-* Some profile activation conditions are changed

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-See also [https://wiki.sapsailing.com/wiki/info/landscape/building-and-deploying#building-deploying-stopping-and-starting-server-instances_app-build-process-for-ios-and-android](https://wiki.sapsailing.com/wiki/info/landscape/building-and-deploying#building-deploying-stopping-and-starting-server-instances_app-build-process-for-ios-and-android).