Fixes #4909
### Motivation

It would be good to expose method `getLastMessageId` in `ConsumerImpl` to a public method. 
eg. some times user would like to know the lag messages; or only consume messages before current time.

### Modifications

- expose method `getLastMessageId` in consumer api.
- add unit test.

### Verifying this change
Ut passed

(cherry picked from commit 93d95c74)

Signed-off-by: xiaolong.ran ranxiaolong716@gmail.com

Fixes #3446 #3565

Motivation
Reset the subscription associated with this consumer to a specific publish time.

* Provide separate module with Pulsar v1 client API wrapper

* Use impl classes rather than API

* Brought back DefaultSchemasTest.testStringSchema