admin: tab system improvement, search: ?search qp

tab content classes (e.g. settingsList, activityList)
can implement "AsTab", "Navigatable" and or "PageEventBindable",
the first giving them a tab name, a subpath and a reloader function,
the second an "isURL" and "navigate" function for loading resources,
the last giving them bind/unbindPageEvent methods. These are looped
through in ts/admin.ts still crudely, maybe tabs.ts could accept "AsTab"
implementers directly.

"Search" class now has a ?search query param which just encodes the
search box content, set when you perform a server search (hit enter or
press the button). ?user queries from the accounts or activity tab will
be converted to this form on loading.

ts/modules/activity.ts

@@ -558,7 +558,9 @@ interface ActivitiesDTO extends paginatedDTO {
     activities: activity[];
 }
 
-export class activityList extends PaginatedList {
+export class activityList extends PaginatedList implements Navigatable, AsTab {
+    readonly tabName = "activity";
+    readonly pagePath = "activity";
     protected _container: HTMLElement;
     protected _sortDirection = document.getElementById("activity-sort-direction") as HTMLButtonElement;
 
@@ -687,18 +689,23 @@ export class activityList extends PaginatedList {
             this._keepSearchingDescription.classList.add("unfocused");
         }
     };*/
-    
-    isActivityURL = () => {
-        const urlParams = new URLSearchParams(window.location.search);
+
+    isURL = (url?: string) => {
+        const urlParams = new URLSearchParams(url || window.location.search);
         const username = urlParams.get("user");
-        return Boolean(username);
+        return Boolean(username) || this._search.isURL(url);
     };
 
-    loadActivityURL = () => {
-        const urlParams = new URLSearchParams(window.location.search);
+    navigate = (url?: string) => {
+        const urlParams = new URLSearchParams(url || window.location.search);
         const username = urlParams.get("user");
-        this._c.searchBox.value = `user:"${username}"`;
-        this._search.onSearchBoxChange();
-        this._search.onServerSearch();
+        let search = urlParams.get("search") || "";
+        if (username) {
+            search = `user:"${username}" ` + search;
+            urlParams.set("search", search);
+            // Get rid of it, as it'll now be included in the "search" param anyway
+            urlParams.delete("user");
+        }
+        this._search.navigate(urlParams.toString());
     };
 }