Implement Emoji Autocompletion and Replacement

app/src/main/assets/emoji.json

.../de/kuschku/quasseldroid/settings/AutoCompleteSettings.kt

.../java/de/kuschku/quasseldroid/settings/MessageSettings.kt

...rc/main/java/de/kuschku/quasseldroid/settings/Settings.kt

...kuschku/quasseldroid/ui/chat/input/AutoCompleteAdapter.kt

.../kuschku/quasseldroid/ui/chat/input/AutoCompleteHelper.kt

...de/kuschku/quasseldroid/ui/chat/input/ChatlineFragment.kt

app/src/main/res/layout/widget_buffer.xml

app/src/main/res/layout/widget_emoji.xml

app/src/main/res/values/strings_preferences.xml

app/src/main/res/xml/preferences.xml

...st/java/de/kuschku/quasseldroid/testutil/StringEscaper.kt

.../java/de/kuschku/quasseldroid/util/emoji/EmojiDataTest.kt

...main/java/de/kuschku/quasseldroid/util/emoji/EmojiData.kt

...e/kuschku/quasseldroid/viewmodel/data/AutoCompleteItem.kt

...ku/quasseldroid/viewmodel/helper/EditorViewModelHelper.kt