Tutorial improvement & deduplication ideas

[Eric-Arellano]

Built off of Qiskit/qiskit-tutorials#1473.

Quantum circuits

• qiskit intro, circuit_basics, and getting_started_with_qiskit are all very similar: write a "get started with Qiskit" tutorial  qiskit#10315
• plotting_data_in_qiskit is replaced by api reference examples: Add common usage explanations and code examples to qiskit.visualization module level API reference page. qiskit#8567
• summary_of_quantum_operations is replaced by api reference examples: Add some explanation and example to circuit library documentation qiskit#7354

Advanced circuits

• advanced_circuits, more like api reference code examples or how-to guide, should be converted to those content type
• operators_overview, more like api reference code examples or how-to guide, should be converted to those content type
• advanced_circuit_visualization, most of the content is covered by one of the how-to guide here: Added how-to guides qiskit#8624
• transpiler_passes_and_passmanager, should be converted to a how-to guide
• pulse_gates, should be converted to a how-to guide
• building_pulse_schedules, should be converted to a how-to guide
• pulse_scheduler, should be converted to a how-to guide
• gathering_system_information, should be converted to a how-to guide. The content is about BackendV1, should be updated to BackendV2 equivalent: write a how-to: Obtaining information about a backend  qiskit#10317

Operators -> Remove in 0.45

Maybe deprecate in 0.44 now.

• operator_flow: remove since optflow is deprecated.
• gradients_framework: remove since optflow is deprecated.

[jakelishman]

I'll transfer this issue over to Qiskit/documentation since I'm fairly sure it belongs there now, just in case there's anything in this that you still want to track (I suspect you've got other trackers, though).