Moved MenuItems to map

-Created a map that maps up MenuItems and the different types of
MenuItems.
-Deleted the previous objects.
-Updated use of the MenuItems to use the new maps.
Removed Renderer interaction from MenuManager

-MenuManager now sets underline withoug calling functions in Renderer. This means MenuManger don't have to use Renderer
-MenuItem now contans the bools of underline and whehter the status have
changed
-Renderer checks whether the MenuItems underline status has changes.
-If it has changed, change the text to either underlined or non-underlined.
-Removed all use, include and forward-declaration in MenuManager.
-Updated GameManager with the above changes.
-Removed all unused functions from Renderer.
-Made all functions in Renderer private where appropriate.