Rename csv-export plugin to grafana-export plugin

[jmcook1186]

Types of changes

• [x] Enhancement (project structure, spelling, grammar, formatting)
• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.

A description of the changes proposed in the Pull Request

This PR clears up the confusion between our builtin csv exporter and the scv exporter plugin. The plugin is designed to output data specifically to support our grafana dashboard, so it is here renamed grafana-exporter. This should help users to distinguish between the two features and make the separation of config in manifests easier.

[pazbardanl]

@jmcook1186 Can you please remind me why are is this plugin renamed? That is -- do we intend the output CSV of this plugin to be used strictly for Grafana? There are no other use cases for it?

[jmcook1186]

@pazbardanl The motivation is that we currently maintain two features that export data to CSV files. One is the builtin csv-export feature in if/builtins that outputs data from the tree to a csv format that is designed to be maximally human readable and "general purpose" - it has its own config that is set in the manifest and command line.

The other is a plugin in if-plugins that also has its own configuration in the manifest and was designed to create a csv intermediary for the grafana dashboard. Users have reported being (understandably) confused by the name collision and having trouble deciphering which config refers to which csv feature in a manifest.

This PR pushes a quick fix to make the distinction between the features more clear by removing the the name collision, but without changing any functionality.

We may well return to this issue and devise a more complete solution later.