Migrate to new Hytale plugin template structure

Replaces the previous Kotlin-based Gradle build and template files with a new Java-based Gradle build system and updated example plugin code. Removes old build scripts, plugin template, and configuration, and introduces a new ExamplePlugin with updated manifest, command, and recipe example. Updates documentation and project configuration to match the new structure and usage.

gradlew

@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -80,11 +80,11 @@ do
     esac
 done
 
-# This is normally unused
-# shellcheck disable=SC2034
-APP_BASE_NAME=${0##*/}
 APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
 
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
 # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
 DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
@@ -143,16 +143,12 @@ fi
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
     case $MAX_FD in #(
       max*)
-        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
-        # shellcheck disable=SC3045
         MAX_FD=$( ulimit -H -n ) ||
             warn "Could not query maximum file descriptor limit"
     esac
     case $MAX_FD in  #(
       '' | soft) :;; #(
       *)
-        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
-        # shellcheck disable=SC3045
         ulimit -n "$MAX_FD" ||
             warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac
@@ -209,12 +205,6 @@ set -- \
         org.gradle.wrapper.GradleWrapperMain \
         "$@"
 
-# Stop when "xargs" is not available.
-if ! command -v xargs >/dev/null 2>&1
-then
-    die "xargs is not available"
-fi
-
 # Use "xargs" to parse quoted args.
 #
 # With -n1 it outputs one arg per line, with the quotes and backslashes removed.