Docs: build doc with new layout for target and version select

docs/_static/js/version_table.js

@@ -0,0 +1,54 @@
+$(document).ready(function() {
+
+    let version = DOCUMENTATION_OPTIONS.VERSION;
+    let language = DOCUMENTATION_OPTIONS.LANGUAGE;
+    let idf_target = DOCUMENTATION_OPTIONS.IDF_TARGET;
+    let pagename = DOCUMENTATION_OPTIONS.PAGENAME + ".html";
+
+    let defaults = DOCUMENTATION_VERSIONS.DEFAULTS;
+    let versions = DOCUMENTATION_VERSIONS.VERSIONS;
+
+    /* Apply the defaults to each version, where needed */
+    for (let i = 0; i < versions.length; i++) {
+        let v = versions[i];
+        for (let d in defaults) {
+            if (!(d in v)) {
+                v[d] = defaults[d];
+            }
+        }
+    }
+
+    /* Find the (relative) base URL for this project, finding a sibling URL will be built as follows:
+    <project_base_url>/<language>/<version>/<idf_target>
+
+    (Where 'idf_target' path element are optional depending on if the project has multiple target support)
+    */
+    let project_base_url = DOCUMENTATION_OPTIONS.URL_ROOT + "../..";
+    if (DOCUMENTATION_OPTIONS.IDF_TARGETS) {
+        project_base_url += "/..";
+    }
+
+    /* Given a version from the list, return the URL to link to it */
+    function getVersionUrl(v) {
+        let result = project_base_url + "/" + language + "/" + v.name;
+        if (v.has_targets) {
+            result += "/" + (idf_target || "esp32");
+        }
+
+        return result + "/";
+    };
+
+    old_ver_list = "";
+
+    for (let i = 0; i < versions.length; i++) {
+        let v = versions[i];
+        let url = getVersionUrl(v);
+
+        if (v.old) {
+            old_ver_list += "<li><a href=\"" + url + "\">" + v.name + "</li>";
+        }
+
+    }
+
+    $( "#version_list" ).append(old_ver_list);
+});