Added option for language selector

Implemented a language selector submenu that can be turned on or off by a config value.

Resolves: panr/hugo-theme-terminal#31

source/js/languageSelector.js

@@ -0,0 +1,12 @@
+const mobileQuery = getComputedStyle(document.body).getPropertyValue("--phoneWidth");
+const isMobile = () => window.matchMedia(mobileQuery).matches;
+
+if(!isMobile()) {
+  languageSelector = document.getElementsByClassName("language-selector-actual")[0];
+  moreLanguagesContainer = document.getElementsByClassName("language-selector-more")[0];
+
+  languageSelector && languageSelector.addEventListener("click", e => {
+    e.stopPropagation();
+    moreLanguagesContainer.classList.toggle("hidden");
+  });
+}