Opportunities to improve the online documentation

[kandersolar]

Originally posted in SunPower/pvfactors#143:

Here's are two things that would be nice to have in the docs, derived largely or entirely from conversation with @spaneja:

Relevant class methods don't have their own docs page

For example: PVEngine has its own page (link), but its fit() method does not, making it hard to know what parameters the method takes (without referring to the tutorials, anyway). I think it should be straightforward to get this working just with sphinx configuration changes.

Irradiance component names and meanings are not documented

It's possible to extract not only total incident and absorbed irradiance but also various sub-components. The docs have an example of this:

solarfactors/docs/tutorials/Run_full_timeseries_simulations.ipynb

Lines 232 to 235 in 21d4865

	"# Get the calculated outputs from the pv array\n",
	"center_row_front_incident_irradiance = pvarray.ts_pvrows[1].front.get_param_weighted('qinc')\n",
	"left_row_back_reflected_incident_irradiance = pvarray.ts_pvrows[0].back.get_param_weighted('reflection')\n",
	"right_row_back_isotropic_incident_irradiance = pvarray.ts_pvrows[2].back.get_param_weighted('isotropic')\n",

It would be nice for the available component names (e.g. reflection) to be listed somewhere, along with specific descriptions of what each name refers to (e.g. does reflection include ground-reflected irradiance, or just row-row reflections?).