Rename bin/newrelic -> bin/newrelic_rpm and remove older bin/newrelic_cmd references and binstub

[dinsley]

Overview

This addresses the issue opened here where there's currently a naming conflict with newrelic-cli and the Ruby agent if both are installed.

It will require the newrelic binstub to be removed in a future major release before the actual name collision issue is solved.

It also removes the older binstub for newrelic_cmd when a previous rename was done, as such this has the potential to be a breaking change for anyone not moved over to the new name.

I've left the version number just a xxx as I'm unsure what version this will be merged into. Happy to update it to whatever, or leave that to y'all when it gets merged!

Reviewer Checklist

• Perform code review
• Add performance label
• Perform appropriate level of performance testing
• Confirm all checks passed
• Add version label prior to acceptance

[fallwith]

Thanks @dinsley for the cleanup and help with getting the project ready for the binary rename in a future major version release!