Add QNode config for mid-circuit measurement options

[mudit2812]

Context:
This PR adds qnode arguments to configure mid-circuit measurement behaviour

Description of the Change:

• Added postselect_mode and mcm_method kwargs to qnode.
  • postselect_mode is a string, and setting it to "fill-shots" will return all samples regardless of validity. Setting it to "hw-like" will scale shots with postselection. Note that "hw-like" with jax will replace invalid samples with INTEGER_MIN_VAL with mcm_method="one-shot". An error will be raised with defer_measurements with `postselect_mode="hw-like"`` and jax jit.
  • mcm_method is a string and can be either "deferred" or "one-shot"
• Update qml.devices.preprocess.mid_circuit_measurements to accommodate mcm configuration options when deciding which transform to use.
• Update QNode._execution_component to use the qml.devices.preprocess.mid_circuit_measurements transform for old API devices.
• Update ExecutionConfig to include an mcm_config and update QNode and qml.execute to set this config.
• Added new section with details about the kwargs to the measurements intro doc.

Note:
When using jax-jit, postselect_mode="hw-like" will add dummy values to the samples with dynamic_one_shot and these won't be used for MPs other than qml.sample. However, with defer_measurements, an error will be raised. This is a limitation of the current implementation of defer_measurements, and I've documented it as such

Benefits:
Users can easily configure how to apply and process mid-circuit measurements.

Possible Drawbacks:
More kwargs to QNode and qml.execute.

Related GitHub Issues:

[mudit2812]

[sc-62105] [sc-62103]

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.67%. Comparing base (c14ce7b) to head (2e3e3a0).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5679      +/-   ##
==========================================
- Coverage   99.67%   99.67%   -0.01%     
==========================================
  Files         414      414              
  Lines       39316    39067     -249     
==========================================
- Hits        39188    38939     -249     
  Misses        128      128              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[dwierichs]

Nice job @mudit2812 !
I may still be confused about a few aspects of the config. Most of the documentation is really clear, there were just a few points where I was not sure I understood what the configuration will end up doing.
I left a number of comments, some of which are very subjective and definitely non-blocking!

[dwierichs]

Thanks for all the explanations and the nice update to behaviour with JITting.
Nice work! 🎉

[vincentmr]

Very nice upgrade, well done @mudit2812 . I'm just sad I'll have to update #5180 for the n-th time accordingly :p

[vincentmr]

Nice work, happy to reapprove @mudit2812 :)

[trbromley]

Approved from the docs perspective, just leaving one suggestion.