Reorganise providers

[frankharkins]

Summary

This PR:

• Removes the "Provider" tag as it's now its own section
• Defines "Provider" as a package that implements Qiskit's provider interface
• Adds a "Hardware" tag to distinguish from circuit simulators

Questions

Should we add a local / cloud simulator tag to distinguish between the two?

[Eric-Arellano]

local / cloud simulator tag

The local/cloud part doesn't seem as relevant. Maybe a "Simulator" tag in general?

[Eric-Arellano]

This needs to regenerate the site, right?

[frankharkins]

We have a Circuit simulator tag for that purpose. However I've since realised we already have a Hardware tag that means something else. Maybe these get a Hardware provider tag?

This needs to regenerate the site, right?

That happens on push to main. Thinking about it now, we should actually take the generated website out of version control.

[Eric-Arellano]

However I've since realised we already have a Hardware tag that means something else.

Hm, what does it mean?

Thinking about it now, we should actually take the generated website out of version control.

Ah, yes please in a dedicated PR explaining the change.

[frankharkins]

Hm, what does it mean?

"For quantum hardware design or quantum control". We could expand the definition though

[Eric-Arellano]

Is this still relevant?