[2.11] Revert PRs added to 2.11 that are not part of 2.11.1 release

[cwperks]

Description

Reverts 2 PRs added after the 2.11.0 release that should not be in the 2.11.1 release:

• [Backport 2.11] Remove Checkstyle redundant implementation. #3486
• [Backport 2.11] Add missing license header (#3467) #3480

Issues Resolved

#3650

Check List

• New functionality includes testing
• New functionality has been documented
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov]

Codecov Report

Merging #3661 (1b86715) into 2.11 (f27dee2) will increase coverage by 0.03%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               2.11    #3661      +/-   ##
============================================
+ Coverage     64.82%   64.85%   +0.03%     
- Complexity     3610     3614       +4     
============================================
  Files           273      273              
  Lines         20024    20024              
  Branches       3346     3346              
============================================
+ Hits          12980    12987       +7     
+ Misses         5399     5395       -4     
+ Partials       1645     1642       -3     

Files	Coverage Δ
...curity/dlic/rest/validation/EndpointValidator.java	94.20% <ø> (ø)

... and 6 files with indirect coverage changes