Update implementation of translate component

[blueaxis]

1. Fix memory leak. The dialog is not being deleted properly when closed, so it is creating a new window every time a translation dialog is opened.
2. Integrate the dialog in WorkspaceView. This should fix the problem above but I have no idea how it will be integrated in global captures.
3. Change the parent of the component. Instead of having it opened in OCRView, we can use signals and slots to pass states to the parent component
4. Improve threading. Right now, there is noticeable lag whenever a translation window is opened.