possible typo in modelchain.ModelChain input naming

[ramaroesilva]

Describe the bug
Was discussing modelchain.ModelChain with @cbcrespo and noticed that in the documentation of modelchain.ModelChain the input for defining the IAM model is named aoi_model. Find below the description:

aoi_model (str, or function, optional) – If not specified, the model will be inferred from the parameters that are common to all of system.arrays[i].module_parameters. Valid strings are ‘physical’, ‘ashrae’, ‘sapm’, ‘martin_ruiz’, ‘interp’ and ‘no_loss’. The ModelChain instance will be passed as the first argument to a user-defined function.

Expected behavior
Is this naming intended or should it be iam_model?

[kandersolar]

I doubt it's a typo (i.e. an accident), but it has irked me for years that it is not called iam_model. aoi_model goes all the way back to #194.

Renaming would take some work, since presumably we would want to rename ModelChain.physical_aoi_loss and friends too. If we go that way, a deprecation period would be needed.

[cwhanse]

There was a time when both terms were heard, AOI and IAM model. I stopped paying attention so maybe one has emerged as consensus.

I'm not opposed to renaming if it improves consistency.

[ramaroesilva]

@kandersolar, maybe this could fit within the GSoC activity to be developed by @cbcrespo (mentored by me and @AdamRJensen), which will demand some work in the modelchain workflow and is described in #2750. Would likely just have to manage the topics in a way that this deprecation period wouldn't stall the rest of the work

@cwhanse now that you mention this, I remember that before using pvlib I wouldn't go for IAM (not sure what was my alternative). I've clearly been evangelized :-)

[echedey-ls]

I agree, two terms for the same thing is a little confusing especially for newbies.
@ramaroesilva , here is a PR I've opened that touches function and attributes renaming. It's kind of noisy but you can get an idea on how a deprecation is implemented in such cases.
https://github.com/pvlib/pvlib-python/pull/2543/changes