feat: allow using the user info menu for offline users

...n/java/de/kuschku/quasseldroid/ui/chat/ToolbarFragment.kt

...chku/quasseldroid/ui/chat/messages/MessageListFragment.kt

...de/kuschku/quasseldroid/ui/chat/nicks/NickListFragment.kt

...a/de/kuschku/quasseldroid/ui/info/user/IrcUserLiveMeta.kt

.../java/de/kuschku/quasseldroid/ui/info/user/IrcUserMeta.kt

.../de/kuschku/quasseldroid/ui/info/user/UserInfoActivity.kt

.../de/kuschku/quasseldroid/ui/info/user/UserInfoFragment.kt

...java/de/kuschku/quasseldroid/util/avatars/AvatarHelper.kt

...a/de/kuschku/libquassel/quassel/syncables/BufferSyncer.kt