Remove commons lang3

[willp-bl]

The new behaviour here should be essentially the same as before, including for null values. The trim() will remove whitespace at the beginning and end of the string so there will need to be >=1 non-whitespace character for trim().length() to be non zero, and therefore for isBlank() to return false..

What problem does the pull request solve?

Removes a dependency

Checklist

• [x] I’ve used the pull request template
• [ ] I’ve written unit tests for these changes
• [x] I’ve update the documentation (in DOCUMENTATION.md)
• [x] I’ve bumped the version number
  • [x] in src/main/resources/application.properties
  • [x] in pom.xml

[samuelhwilliams]

Thanks @willp-bl - this looks good to me 👍 Would you mind doing a patch bump on the Java client version and including a line in the changelog? Then I think we can merge this 🙌