Improve Primitive Introduction Pages

[kaelynj]

trafficstars

URL, if applicable

https://docs.quantum.ibm.com/guides/primitives

Describe the new content you are requesting.

Our introduction to primitives page at this point reads more like a migration guide rather than a proper introduction to the concept and usage of primitives. I'd suggest we reorganize the content in here (or perhaps incorporate the content included being created in #1566 once that's done).

If this new content request is accepted, do you want to write the content?

I will write a draft of the proposed content

[beckykd]

Can you also add that Sampler requires circuit measurements?

[javabster]

wait until primitives v1 removal is done to work on this

[kaelynj]

Will check the current status of this issue given that #1809 has been closed.

[kaelynj]

Ok looking over the updated page, I just have a few tweaks I'd like to add in that I'll list here for me to keep track:

• [x] Rework the intro section to provide an initial definition of the Sampler and Estimator primitive before moving on to discussing where they are defined/implemented (or just add links to their section to draw the eyes more).
• [x] Move 'Benefits of Qiskit Primitives' to just below intro section.
• [x] Explain more about the relationship between the qiskit implementations of the primitives and the Qiskit Runtime service.
• [x] Add more links in general for users to follow

[beckykd]

Per @jyu00

• [x] the How to use Qiskit primitives section should separate out the base classes from the qiskit implementations