Encourage users to classify using `simp::classes` rather than `classes`

This log records a significant past decision that hasn't been widely circulated.

Status	DECIDED
Impact	LOW
Driver	Trevor Vaughan
Approver	Trevor Vaughan
Contributors	Trevor Vaughan Chris Tessmer Liz Nemsick
Informed
Due date	01 Jul 2019
Outcome	We should encourage users to add their own classifications using the `simp::classes` parameter instead of the (now-legacy) `classes` lookup key.

Background

https://simp-project.slack.com/archives/CA4EMBXEJ/p1562344381223000	https://app.slack.com/client/TA4GPKY1M/CA4EMBXEJ/thread/CA4EMBXEJ-1562359521.248400

Relevant data

Options considered

Option 1:

Description We should encourage users to add their own classifications using the simp::classes parameter instead of the (now-legacy) classes lookup key.

Pros and cons

The simp::classes parameter is already provided by the simp profile to support scenarios' internal classifications.

Reusing simp::classes for user classifications makes them subject to the same flow control (e.g., knockout prefixes) as the SIMP's internal classifications.

This avoids needing a lot of extra documentation to enable agentless deployments to either reuse the site.pp classification strategy, or maintain separate (and recurring) classification guidance for site.pp+classes and simp::classes.

Combining users' and the simp's internal classification data streams joins two separate concerns (impact: ¯\_(ツ)_/¯ )

Estimated cost

LOW

Action items

Outcome

We should encourage users to add their own classifications using the simp::classes parameter instead of the (now-legacy) classes lookup key.