Implement the "inline" account switch button

Make the account switch listview into a widget

src/widgets/accountswitchwidget.cpp

@@ -0,0 +1,64 @@
+#include "accountswitchwidget.hpp"
+#include "accountmanager.hpp"
+
+namespace chatterino {
+namespace widgets {
+
+AccountSwitchWidget::AccountSwitchWidget(QWidget *parent)
+    : QListWidget(parent)
+{
+    static QString anonUsername(" - anonymous - ");
+
+    this->addItem(anonUsername);
+
+    for (const auto &userName : AccountManager::getInstance().Twitch.getUsernames()) {
+        this->addItem(userName);
+    }
+
+    this->refreshSelection();
+
+    QObject::connect(this, &QListWidget::clicked, [this] {
+        if (!this->selectedItems().isEmpty()) {
+            QString newUsername = this->currentItem()->text();
+            if (newUsername.compare(anonUsername, Qt::CaseInsensitive) == 0) {
+                AccountManager::getInstance().Twitch.currentUsername = "";
+            } else {
+                AccountManager::getInstance().Twitch.currentUsername = newUsername.toStdString();
+            }
+        }
+    });
+}
+
+void AccountSwitchWidget::refresh()
+{
+    this->refreshSelection();
+}
+
+void AccountSwitchWidget::refreshSelection()
+{
+    this->blockSignals(true);
+
+    // Select the currently logged in user
+    if (this->count() > 0) {
+        auto currentUser = AccountManager::getInstance().Twitch.getCurrent();
+
+        if (currentUser->isAnon()) {
+            this->setCurrentRow(0);
+        } else {
+            const QString &currentUsername = currentUser->getUserName();
+            for (int i = 0; i < this->count(); ++i) {
+                QString itemText = this->item(i)->text();
+
+                if (itemText.compare(currentUsername, Qt::CaseInsensitive) == 0) {
+                    this->setCurrentRow(i);
+                    break;
+                }
+            }
+        }
+    }
+
+    this->blockSignals(false);
+}
+
+}  // namespace widgets
+}  // namespace chatterino