Feat add generate builder

[DumiJDev]

No description provided.

[DumiJDev]

A method with many params can be verbose, flow API is more flexible and params can be passed calling the setter method, like:

Old method (verbose):

    Generator.Response r = m.generate(UUID.randomUUID(), ctx, 0.0f, 256, (s, f) -> {});

Flow API:

Generator.Response r = m.generateBuilder()
            .session(UUID.randomUUID()) //By default, UUID.randomUUID()
            .promptContext(ctx)
            .ntokens(256) //By default, 256
            .temperature(0.0f) //By default, 0.0f
            .onTokenWithTimings((s, aFloat) -> {}) //By default, (s, aFloat) -> {}, nothing
            .generate();

Generator.Response r = m.generateBuilder()
            .promptContext(ctx) //Required or can use prompt(String)
            .generate();

In first time, it appears verbose, but is very flexible, some params has a default value.