Replaces the minimap editor build with EditorView methods

The `EditorView` class already provides us with methods to
generates the lines html. It’s not only faster ; generating the minimap
for a ~200 lines file goes from 65ms down to 15ms without any other
optimization ; it also allow us to benefit from the soft wrapping
settings of the editor view without hassle. The minimap now completely
match the editor view in content.
Adds a wrapper between the minimap and its content

It will allow to separate the positioning of the minimap and the
scaling/transformation of its content. It’ll also allow to not depend
on the editor view state in transform computation (we’ll only rely on
the minimap content)
 Adds a margin on the editor scroll view to fit the minimap in

The goal here is to have the minimap taking 10% of the pane, the editor
scroll view and the scrollbar are moved 10% from the right border to
mimic the ST behavior where the buffer doesn’t run behind the minimap.