Create mobile platforms maintenance docs

[premun]

Context

The Android and Apple platforms have many non-trivial dependencies such as the Android and Apple mobile operation systems, tooling such as Xcode, mlaunch and adb...
These dependencies will need maintenance in order to be supported by Helix.

Goal

We need to roughly estimate the rhythm and release cycles with which these are expected to be updated and describe operational costs and needs to keep all of the Android and Apple platforms supported in Helix.

This dependency eco system needs to be captured in a document or wiki page so that:

• We are aware of all the dependencies of these platforms
• We are able to estimate the operational costs connected to keeping these up to date
• We have instructions to update all necessary parts of the system (from signing certificates to physical device management)
• We understand the division of responsibilities so that we can triage which team should handle given update/fix

[premun]

Re-opening as we will also compile a maintenance plan and form an agreement with the client teams about strategy to decide ownership of future changes in the mobile device area.

Currently the proposal is here

[premun]

This has been sent out with the client teams and approved