Allow apps to specify mod version requirements (#798)

* Allow apps to specify mod version requirements

* Allow a function in requires field and move to `readConfig()`

* Add `server_mods` to system_info()

* Add prefixes and default to `=`

* Added docs for `requires` and for `system_info('server_mods')`

* Better docs for requires (mention * and available prefixes)

* Update docs/scarpet/api/Overview.md

* Update docs/scarpet/api/Overview.md

* Update docs/scarpet/api/Overview.md

Co-authored-by: gnembon <41132274+gnembon@users.noreply.github.com>

src/main/java/carpet/script/CarpetScriptServer.java

@@ -270,12 +270,14 @@ public class CarpetScriptServer
         }
         //addEvents(source, name);
         String action = reload?"reloaded":"loaded";
+        
         Boolean isCommandAdded = newHost.addAppCommands(s -> {
             if (!isRuleApp) Messenger.m(source, s);
         });
         if (isCommandAdded == null) // error should be dispatched
         {
-            removeScriptHost(source, name, false, false);
+            removeScriptHost(source, name, false, isRuleApp);
+            return false;
         }
         else if (isCommandAdded)
         {