[Java] Standardise Logger naming

As per: https://github.com/apache/arrow/pull/7100#discussion_r421884919

We use LOGGER and logger interchangeably and should choose one

**Reporter**: [Ryan Murray](https://issues.apache.org/jira/browse/ARROW-8739) / @rymurr

_{**Note**: *This issue was originally created as [ARROW-8739](https://issues.apache.org/jira/browse/ARROW-8739). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Start with the referenced pull request discussion, then search the Java repository for LOGGER and logger usages to determine the affected files. Done means the project uses one logger naming convention consistently; no specific tests or test files are mentioned in the issue.

Written by the indexing model from the issue text.