Add confirmation to service delete commmand

[kkemple]

TODO:

• Update CHANGELOG.md* with your change (include reference to issue & this PR)
• Make sure all of the significant new logic is covered by tests
• Rebase your changes on master so that they can be merged easily
• Make sure all tests and linter rules pass

*Make sure changelog entries note which project(s) has been affected. See older entries for examples on what this looks like.

This PR adds a confirmation to the service:delete command in the CLI.

[apollo-cla]

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