feat: Multiplayer (#2)

Make this game multiplayer.

Setup:
- `common` for common classes used both by the server and the client
- `game` the actual client
- `server` the server

Reviewed-on: https://gitea.local.jzitnik.dev/jzitnik/game/pulls/2
Co-authored-by: jzitnik-dev <email@jzitnik.dev>
Co-committed-by: jzitnik-dev <email@jzitnik.dev>

.idea/misc.xml

@@ -1,17 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="EntryPointsManager">
-    <list size="3">
-      <item index="0" class="java.lang.String" itemvalue="cz.jzitnik.annotations.EventHandler" />
-      <item index="1" class="java.lang.String" itemvalue="cz.jzitnik.annotations.ui.KeyboardPressHandler" />
-      <item index="2" class="java.lang.String" itemvalue="cz.jzitnik.annotations.ui.MouseHandler" />
-    </list>
-    <writeAnnotations>
-      <writeAnnotation name="cz.jzitnik.annotations.injectors.InjectConfig" />
-      <writeAnnotation name="cz.jzitnik.annotations.injectors.InjectDependency" />
-      <writeAnnotation name="cz.jzitnik.annotations.injectors.InjectState" />
-    </writeAnnotations>
-  </component>
   <component name="ExternalStorageConfigurationManager" enabled="true" />
   <component name="MavenProjectsManager">
     <option name="originalFiles">
@@ -20,7 +8,5 @@
       </list>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_25" default="true" project-jdk-name="openjdk-25" project-jdk-type="JavaSDK">
-    <output url="file://$PROJECT_DIR$/out" />
-  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_25" default="true" project-jdk-name="openjdk-25" project-jdk-type="JavaSDK" />
 </project>