Update copyright notice & footer (#2496)

## Description:

* Update copyright notice to "OpenFront and Contributors"

* remove the "how to play" on the footer, since that will be moved to
the death screen.

* Removed css and used tailwind instead for better mobile support


Describe the PR.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

src/client/GameStartingModal.ts

@@ -93,7 +93,7 @@ export class GameStartingModal extends LitElement {
     }
 
     .copyright {
-      font-size: 32px;
+      font-size: 20px;
       margin-top: 20px;
       margin-bottom: 10px;
       opacity: 1;
@@ -118,7 +118,7 @@ export class GameStartingModal extends LitElement {
   render() {
     return html`
       <div class="modal ${this.isVisible ? "visible" : ""}">
-        <div class="copyright">© OpenFront</div>
+        <div class="copyright">© OpenFront and Contributors</div>
         <a
           href="https://github.com/openfrontio/OpenFrontIO/blob/main/CREDITS.md"
           target="_blank"