Update dynamic circuits guides to describe new features [27 June]

[beckykd]

URL, if applicable

These guides will need to be updated (no need for a migration guide):

• https://docs.quantum.ibm.com/guides/classical-feedforward-and-control-flow
• https://docs.quantum.ibm.com/guides/runtime-options-overview#feature-compatibility (investigate)

Describe the new content you are requesting.

Overview:

Starting on June 2, we are rolling out a new version of dynamic circuits. This next version will allow users to run dynamic circuits at utility scale and comes with improvements in speed, quality, and usability, including

Takes advantage of the Gen3 Engine stack that gives a 75x speedup in execution
Parallel execution of branches reduces circuit duration and improves result quality
Improvement in mid circuit measurement
Better integration with dynamical decoupling
More visibility in circuit timing information
Some of these improvements will not be available in the initial release and will come later in the year.

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

I will write a draft of the proposed content

[javabster]

first step we should do soon is to sync with @jyu00 on whether there is anything to tackle already or do we need to wait. and should we document any experimental features earlier than june 2

[jyu00]

We are starting the alpha testing on May 1, but we don't need doc updates because we'll work directly with users who want to try the alpha version.

For the June 2 release, we'll need doc updates on the new features. Mid-May is probably a good time to start writing that content.

[javabster]

cc @miamico

[abbycross]

@jyu00 Are the planned new features in a stable-enough place to start on the docs now?

[jyu00]

The release date has changed, but we should start now. In addition to the 2 pages listed in the OP, we should also (1) add a new page on stretch, and (2) revisit the hardware limitation page

[abbycross]

The release date has changed, but we should start now. In addition to the 2 pages listed in the OP, we should also (1) add a new page on stretch, and (2) revisit the hardware limitation page

Ok sounds good. Are you our main content provider for these things, or should we bug someone else :)

[abbycross]

Also, as part of revisiting the hardware limitation page, consider converting it to .mdx, per the discussion on this PR