Drop "Send to cloud" tool and associated cloudauthz code

[jdavcs]

Fixes #18098

I'm dropping more code than indicated in the issue because dropping the initial code exposed more unused code, including the CloudAuthz model.

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[mvdbeek]

Thank you @jdavcs!