Update Admin CSS / Few css fixes

Changed `code` color to be a little lighter, more contrast / easier to read (From #999 to #c3c3c3)
Added Readonly style, was white box with grey letters. Changes to Dark grey box and white letters.
Changed cursor for disabled / read-only to `not-allowed` instead of `text`
Closes #1918 -> Dropdown text was grey with a grey background.
Added Green and Yellow Text colors
Added Text-Danger
Changed Link color, to be a tad lighter
Added well/well-sm/well-lg to pterodactyl.css
Changed well to match the dark theme.
Hovering over Start / Restart show respective colors Green / Blue

resources/views/admin/users/index.blade.php

@@ -58,7 +58,7 @@
                                 <td>{{ $user->username }}</td>
                                 <td class="text-center">
                                     @if($user->use_totp)
-                                        <i class="fa fa-lock text-green-500"></i>
+                                        <i class="fa fa-lock text-green"></i>
                                     @else
                                         <i class="fa fa-unlock text-red"></i>
                                     @endif