Various QoL fixes for Desktop App (#2999)

* Some ESLint fixes

* Add login/logout signal to API, clear mentions on logout and flush cookies on login/logout

* Fix issue where local and HTTP-only servers would not validate correctly

* Reduce noise of renderer logging, adjust a few local renderer logs to be louder when needed

* Fallback to beginning of hostname for servers that don't change the site name

* Fix Save Image crash

* Update the name for insecure servers too

* Fix test

* Fix lint

* Reduce repetition

src/renderer/components/MainPage.tsx

@@ -162,7 +162,7 @@ class MainPage extends React.PureComponent<Props, State> {
 
         // set page on retry
         window.desktop.onLoadRetry((viewId, retry, err, loadUrl) => {
-            console.log(`${viewId}: failed to load ${err}, but retrying`);
+            console.error(`${viewId}: failed to load ${err}, but retrying`);
             const statusValue = {
                 status: Status.RETRY,
                 extra: {
@@ -179,7 +179,7 @@ class MainPage extends React.PureComponent<Props, State> {
         });
 
         window.desktop.onLoadFailed((viewId, err, loadUrl) => {
-            console.log(`${viewId}: failed to load ${err}`);
+            console.error(`${viewId}: failed to load ${err}`);
             const statusValue = {
                 status: Status.FAILED,
                 extra: {