Improve the buttons in the main user interface

[latenitefilms]

Florian Duffe writes:

For your first patch I only would recommend a few UI-Improvements:
The buttons in the left lower corner for folders and items are very similar and when you don't use it for a while you gotta think again which is which. the + and - are very small. Maybe it would be a good idea to move "New item" and "Remove item" below the window with the items in it.

[latenitefilms]

@florian-duffe writes:

Chris wrote in FCP-WFG: "it gets complicated when you can hide the sidebar."
my suggestion: why not move "remove folder" and "remove item" into the right click context menu of the respective items. Additionally: enable removing with select and hit "delete" key.
Then just have a big + sign at the bottom or the top of the folder list and the items window.
Compare MacOS contacts app: New list is a hiding + in a circle at the top, new card is a big + at the bottom of the active card.
I guess they aren't consistent there either. I would go for a big visible + sign.

I feel like @IAmVigneswaran had similar thoughts.