Studio: refactoring font-size to use existing Sass scale-based placeholders

cms/static/sass/_base.scss

cms/static/sass/assets/_graphics.scss

cms/static/sass/elements/_controls.scss

cms/static/sass/elements/_footer.scss

cms/static/sass/elements/_forms.scss

cms/static/sass/elements/_header.scss

cms/static/sass/elements/_modal-window.scss

cms/static/sass/elements/_modal.scss

cms/static/sass/elements/_navigation.scss

cms/static/sass/elements/_sock.scss

cms/static/sass/elements/_system-feedback.scss

cms/static/sass/elements/_tender-widget.scss

cms/static/sass/elements/_typography.scss

cms/static/sass/elements/_vendor.scss

cms/static/sass/elements/_xblocks.scss

cms/static/sass/elements/_xmodules.scss

cms/static/sass/views/_assets.scss

cms/static/sass/views/_checklists.scss

cms/static/sass/views/_container.scss

cms/static/sass/views/_dashboard.scss