Create basic structure for Android devonfw guide

[arnecor]

The guide is the core artifact of each devonfw project. To get startet, the first step is to review the existing documentation and guidelines. The devon4j project already has an extensive guide, which can be seen as example for our sturcture.

Suggested first steps:

• Get an overview of the devon4j documentation (as reference/example):
• Review existing documentation on nscomm and identify which chapters would be relevant for Android. (e.g. architecture principles)
• Create Wiki on https://github.com/devonfw-forge/devon4android/wiki
• Create/migrate content
• Create issues for missing content

Details can be discussed below (Which chapters are relevant for Android?).