Within this commit apart of `ChatContextMenuView` and `MessageContextMenuView`
some other things are fixed:
- pinned messages model (`asyncFetchChatMessagesTask`), which was corrupted most
likely by resolving conflicts
- `pinned by` part of the pinned messages
- set/remove local nickname for a contact
- contacts in a message list and pinned by name, contact in a pinned message list
and pinned by name, one to one chat details and chat tool bar are updated in a way
that they are responsive to the contact's updates
- pinned messages updated received from remote (from the `status-go`) is handled
Fixes#4366
- admin flag exposed to qml for chat/channel
- `CreateChannelPopup` updated
- `createPopup` function added to the `Global` singleton
- `PinnedMessagesPopup` component moved to `AppMain` and shared
among components beneath
- `chatType` added to `Constants` to group chat type related values
- `messageContentType` added to `Constants` to group message content type related
values
- `MessageStore` maintained per message list now
- added new `ChatContentView` component used to display chat/channel content
- components updated to display messages from the new backend
- `StatusChatToolBar` appropriately updated
- mute/unmute feature added to chat/channel list as well as to `StatusChatToolBar`