Rework dictionary import UX

[Kuuuube]

Adds drag and drop functionality and the option to import dictionaries from a url.

[Kuuuube]

Fixed up the UI and added drag and drop functionality.

Upon clicking Import	Dragging file

[Kuuuube]

Current UI:

Upon clicking Import	Dragging file

I've also left in the Import from URLs option for now but it only appears if advanced settings are enabled and the textarea is much smaller.

[MarvNC]

If you can click the big button to open the file picker maybe the bottom button is redundant?

[jamesmaa]

My UI hot take: drag-and-drop is an advanced user feature and can actively work against most users' intuition of how to upload files.

My SWAG is that 80% of users prefer Click to Upload over drag and drop.

Here are some examples of drag and drop UI's in other popular platforms:
Google drive: No indication it is supported but if you drag and drop into gdrive it works

FB: Indicates both options but prioritizes clicking the button first and de-emphasizes drag and drop

Github:

Youtube: Prioritizes drag and drop but adds a clear button to let users know a file browser is available as well

My suggestion is to go with FB's approach as it makes the upload file button much bitter and supports drag and drop for other users

[Kuuuube]

Current UI:

Upon clicking Import	Hovering over with mouse	Dragging file

[jamesmaa]

I didn't review the code details very carefully but this looks fine and looks well tested/polished and the breakage risk is low so