[TASK] Change documentation options in doxyfile

- Disable group graph
- Disable inline code for headerfiles

Change-Id: I89f1fbf4f26ea70d5dda8a09e9d5d7ce1f30ca04
Reviewed-on: http://brateggevoat1/gerrit/1372
Tested-by: Jenkins <jenkins@brateggevoat1.br-automation.co.at>
Reviewed-by: Josef Baumgartner <josef.baumgartner@br-automation.com>