[SPARK-14392][ML] CountVectorizer Estimator should include binary toggle Param

## What changes were proposed in this pull request?

CountVectorizerModel has a binary toggle param. This PR is to add binary toggle param for estimator CountVectorizer. As discussed in the JIRA, instead of adding a param into CountVerctorizer, I moved the binary param to CountVectorizerParams. Therefore, the estimator inherits the binary param.

## How was this patch tested?

Add a new test case, which fits the model with binary flag set to true and then check the trained model's all non-zero counts is set to 1.0.

All tests in CounterVectorizerSuite.scala are passed.

Author: wm624@hotmail.com <wm624@hotmail.com>

Closes #12200 from wangmiao1981/binary_param.