New app for ARIMA-style feed analysis: show plots from #1009

[trentmc]

Background / motivation

Parent epic: #1006 "Explore SARIMAX modeling"

Top-level goal: Help user answer which of which transform to use {0, B0, B1, B2}, to (a) achieve stationarity; and (b) see how well the signal can decompose into trend / seasonal / residual.

Towards that goal, issue #1009 figured out the math and the plots in unit tests. "ARIMA-style feed analysis: for {BoxCox=T/F, diff=0,1,2}, plot the seasonality and ACF/PACF"

This issue follows up on # 1009, by putting the plots into a standalone app. (That will be side-by-side with sim plots app, pdr analytics app, etc). Main goal of the app is to analyze feeds. To start, it will be ARIMA-style analysis. Over time, we'll get more info.

TODOs

• Build the "main prototype" shown in # 1009 as a standalone app.