[release] 1.12.0

As recently announced, here is this month's release. This release contains quite a lot of redesign (especially in the search and profile screen, navigation drawer, bottom navigation), taking into account all your suggestions, the possibility to highlight occurrences of textual queries in search results, the list of uploaded media (with the possibility to remove images), several improvements in Markdown rendering and localization updates. Moreover, this is the first production release featuring the new amazing application icon, which is part of the identity of this project. All people who contributed and who have all my gratitude, are listed in the "Acknowledgements" screen.