OP-168 Converting all css to less

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OP-168 Making all the backend admin CSS specific to PresideCMS by wrapping in a .presidecms class which is set on the html tag of the admin HTML layouts

This also allows us to include the stylesheets in the front end when a user is logged in and style the front end toolbars and interactions in the same way without interfering with site styles. So long as any Preside elements are wrapped in a container that has a class of 'presidecms', we're golden

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OP-168 Making the frontend isolated styles for preside work well

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OP-168 Making the bootbox modal work with Preside styles in the front end

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