2021-November-09 - Prerelease - 2.6.453

Update checkstyle to latest version (8.45) & Prune Validations (#9755)

* Update checkstyle to latest version (8.45) & Prune Validations

First, we get a brand new checkstyle.xml file from google-java.
This new file is compatible with the latest checkstyle 8.45.

Then rules were removed to make the current code pass checkstyle.
Further, most formatting rules were removed, we will rely on
'spotlessCheck' to verify formatting.

Next, the suppression file seemingly has no effect. It was removed.
The few exceptions we cannot avoid were simply added to the
'MemberName' regex white list.

Resolves: #7788