Remove theme manager in favour of webassets

gallery/themes/default/components/buttons/info-button.sass

@@ -1,41 +0,0 @@
-.info-button
-    margin: 0
-    padding: 0
-
-    width: auto
-    height: auto
-
-    position: fixed
-    bottom: 0.75rem
-    right: -3rem
-
-    display: flex
-    justify-content: center
-    align-items: center
-
-    background-color: RGB($bg-300)
-    color: RGB($fg-white)
-    border-radius: $rad
-    border: none
-    opacity: 0
-
-    z-index: 20
-    cursor: pointer
-    transition: all 0.2s cubic-bezier(.86, 0, .07, 1)
-
-    &:hover
-        color: RGB($info)
-
-    svg
-        margin: 0.5rem
-
-        width: 1.25rem
-        height: 1.25rem
-
-    &.show
-        right: 0.75rem
-        opacity: 1
-
-@media (max-width: $breakpoint)
-    .info-button
-        bottom: 4.25rem