Use an Enum for meas_level and meas_return

What is the expected enhancement?

meas_level seems to be the perfect candidate for an Enum class. The change would improve readability and clarity around raw numbers in the code. For instance: meas_level=MeasLevel.CLASSIFY is more suggestive of turning readout results into classified {0,1} bits than meas_level=2. This also fits with most other leveling systems in python, such as logging levels (https://docs.python.org/3/library/logging.html#levels). This could also apply for meas_return.

My proposal:

class MeasLevel(Enum):
    RAW = 0
    KERNELED = 1
    CLASSIFIED = 2

class MeasReturn(Enum):
    SINGLE = "single"
    AVG = "avg"

I’d love any recommendations for the meas_level names.

Likely this would induce another change further down the line to pull .value out.

[SooluThomas]

I might circle back to this.

[ajavadia]

i support this as i’m often confused about whether 0 is lower or 2