add buttons to sign in

src/page/SignIn/SignIn.svelte

@@ -8,8 +8,10 @@
 
 <div class={style.root}>
     <h1>Log In</h1>
-    <p align='center'>
+    <p style="text-align:center">
         To continue, you must choose a homeserver<br/>
-        <input type='text' value={homeserver}>
+        <input type='text' value={homeserver}><br/>
+        <button>What is a homeserver?</button>
+        <button>Explore homeservers</button>
     </p>
 </div>