"bin/doctor" requires Ruby and Gems to be installed

[benthorner]

Background

We refer to this utility in our troubleshooting guidance, but using it requires someone to install Rbenv, Ruby and Gems. This can take a long time if someone doesn't already have the required version of Ruby installed on their system. Having to do all these steps also makes it likely the user will need support with the support utility 😆.

Suggestions

Since most of the checks are just simple shell commands, we could rewrite the script in bash to avoid the need for Ruby / Gems. Alternatively, we could raise a PR, or conduct an informal poll, to remove the utility: we should prioritise fixing problems at source, and empowering people to fix harder problems themselves, with guidance.