Remove deprecated navbar and header

sass/components/navbar.sass

@@ -1,57 +0,0 @@
-.navbar-item
-  .title,
-  .subtitle
-    margin-bottom: 0
-  // Responsiveness
-  +mobile
-    &:not(:last-child)
-      margin-bottom: 10px
-
-.navbar-left,
-.navbar-right
-  .navbar-item
-    &:not(:last-child)
-      margin-right: 10px
-    // Modifiers
-    &.is-flexible
-      flex-grow: 1
-
-.navbar-left
-  // Responsiveness
-  +mobile
-    & + .navbar-right
-      margin-top: 20px
-  +tablet
-    align-items: center
-    display: flex
-
-.navbar-right
-  // Responsiveness
-  +tablet
-    align-items: center
-    display: flex
-    justify-content: flex-end
-
-.navbar
-  @extend .block
-  align-items: center
-  justify-content: space-between
-  code
-    border-radius: $radius
-  img
-    display: inline-block
-    vertical-align: top
-  // Modifiers
-  &.is-mobile
-    display: flex
-    & > .navbar-item
-      &:not(:last-child)
-        margin-bottom: 0
-      &:not(.is-narrow)
-        flex-grow: 1
-  // Responsiveness
-  +tablet
-    display: flex
-    & > .navbar-item
-      &:not(.is-narrow)
-        flex-grow: 1