Elastic: Toolbar/menus/layout refactoring

Refactoring for better consistency and simplicity.

5KB less in size of (minified) styles.css file.

Layout changes:

• body > #layout > .menu -> #layout-menu
• body > #layout > .list -> #layout-list
• body > #layout > .sidebar -> #layout-sidebar
• body > #layout > .content -> #layout-content

Toolbar/menu changes:

• .toolbar -> .toolbar.menu
• .toolbarmenu -> .menu.listing
• .menu-button -> .task-menu-button
• .pagenav.toolbar -> .pagenav.menu
• #taskmenu -> #taskmenu.menu.toolbar
• .image-tools .menu -> .image-tools .menu.toolbar
• required .disabled class to de-activate menu items
• .button class is not required on .menu children
• merge toolbar.less and taskmenu.less into menu.less
• @color-toolbarmenu-hover -> @color-menu-hover
• @color-toolbarmenu-hover-background -> @color-menu-hover-background

Also cleaned/removed some code in spellchecker.js. Made .googie_list a list not table.