Some Branch methods are missing in the client

[andrii-bodnar]

Crowdin's string-based projects include some additional API methods for working with branches:

• Get Cloned Branch
• Clone Branch
• Check Branch Clone Status
• Merge Branch
• Check Branch Merge Status
• Get Branch Merge Summary

These methods should also be included in this API client, along with the existing branch methods, and covered by unit tests.

https://github.com/crowdin/crowdin-api-client-java/blob/master/src/main/java/com/crowdin/client/sourcefiles/SourceFilesApi.java