Remove eclipse formatter plugin

[agilob]

I doesn't seem to be used as formatter:format is not used anywhere in this repo

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh
  

  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  For Windows users, please run the script in Git BASH.
• File the PR against the correct branch: master (5.3.0), 6.0.x
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

[agilob]

it's not part of compile stage, and not triggered by name

[agilob]

@wing328 @jimschubert

[agilob]

when triggered manually on master produced 555 changed files, 100% not used

[wing328]

A little big more background on this: in short, we didn't activate the plugin since using this change will result in a lot of changes to the master and lots of PRs (pending review) will need to be rebased or manually resolved the conflicts, which is not something we want.

[agilob]

Yes, I agree, if anything this plugin should be triggered by git commit hook