web: move all strings to i18n & improve a11y

- omnibox is now fully usable with a screen reader
- back button is now interpreted as such
- subtext now accepts line breaks

web/src/components/sidebar/CobaltLogo.svelte

@@ -13,6 +13,7 @@
         align-items: center;
         padding: calc(var(--padding) * 2 - 2px);
     }
+
     @media screen and (max-width: 535px) {
         #cobalt-logo {
             display: none;