[Java][New Feature] Add Java builder for table object

[eeoun]

In java part of flatbuffers
Generate a Table Object is really annoying.
I'm planning add some code so it can be generate a InnerClass V1Builder in Table Class. .i.e HelloResponse.V1Builder HelloResponse.newV1Builder

And in the finally it show's like that

    @Test
    public void flatbuffers_tables() throws Exception {
        var uuid = UUID.randomUUID().toString();

        Allocator<HelloRequest>[] tables = new Allocator[]{
                HelloRequest.newBuilder()
                        .name(uuid),
                HelloRequest.newBuilder()
                        .name("uuid")
        };

        Allocator<Vec3>[] vec3Builders = new Allocator[]{
                Vec3.createVec3(1, 2, 3, new float[]{1, 2, 3}),
                Vec3.createVec3(1, 2, 3, new float[]{1, 2, 3}),
                Vec3.createVec3(1, 2, 3, new float[]{1, 2, 3})
        };

        var builder = HelloResponse.newBuilder()
                .singleTable(tables[0])
                .arrayTable(tables)
                .singleStruct(vec3Builders[0])
                .arrayStruct(vec3Builders)
                .singleInt(114514)
                .arrayInt(1, 2, 3, 4)
                .singleString("a")
                .arrayString("a", "b");

        var response = builder.asObject();

        var buffer = builder.toBuffer();

        var fromBuffer = HelloResponse.getRootAsHelloResponse(buffer);

        Assertions.assertEquals(uuid, response.singleTable().name());
        Assertions.assertEquals(uuid, fromBuffer.singleTable().name());

        Assertions.assertEquals(tables.length, response.arrayTableLength());
        Assertions.assertEquals(tables.length, fromBuffer.arrayTableLength());

        Assertions.assertEquals(uuid, response.arrayTable(0).name());
        Assertions.assertEquals(uuid, fromBuffer.arrayTable(0).name());

        Assertions.assertEquals(114514, response.singleInt());
        Assertions.assertEquals(114514, fromBuffer.singleInt());

        Assertions.assertEquals(3, response.arrayStructLength());
        Assertions.assertEquals(3, fromBuffer.arrayStructLength());

//        Assertions.assertEquals(4, response.vIntS(3));
//        Assertions.assertEquals(4, fromBuffer.vIntS(3));

        Assertions.assertEquals(4, response.arrayIntLength());
        Assertions.assertEquals(4, fromBuffer.arrayIntLength());


    }

Although Builder use a lot of lambda, so it may cause memory increase.
Since you're using Java anyway, being generous with memory shouldn't be a problem.