[ClientCore] Introduce Union type

[mssfang]

This PR brings the idea of Union type to the client core:

A Union type could be one of the mixed types. For example,

1, Create an instance of mixed types, Integer, Double, and String, you can use the following code

Union.ofTypes(String.class, Integer.class); 
// or primitive types
Union.ofTypes(int.class, double.class); 
// or Paramatered types (like collections)
Union.ofTypes(new GenericParameterizedType(List.class, String.class), new GenericParameterizedType(List.class, Integer.class))

2, Set the value

union.setValue("Hello");

3, How to consume the value:

3.1, In Java 17+, use the switch:

switch (union.getValue()) {
    case String s -> System.out.println("String value: " + s);
    case Integer i -> System.out.println("Integer value: " + i);
    default -> throw new IllegalArgumentException(
        "Unknown type: " + union.getType().getTypeName());
}

or use if-else:

if (value instanceof String) {
    String s = (String) value;
    System.out.println("String value: " + s);
} else if (value instanceof Integer) {
    Integer i = (Integer) value;
    System.out.println("Integer value: " + i);
} else {
    throw new IllegalArgumentException("Unknown type: " + union.getCurrentType().getTypeName());
}

3.2, use the tryConsume lambda method:

union.tryConsume(v -> System.out.println("String value: " + v), String.class);

[azure-sdk]

API change check

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io.clientcore:core