Update custom CCI flows to improve documentation

[samanthashain]

What are you trying to accomplish?

• distinguish between standard and custom cci flows
• help contributors understand that custom cci flows only work in this repo
• workaround per this open issue: https://github.com/SFDO-Tooling/CumulusCI/issues/1350

What do you think might be involved in the solution?

• Determine reasonable naming convention
• update custom cci flows in cumulusci.yml file
• audit docs and update references to custom cci flows if necessary

[programmer2coder]

During today's working meeting, we (me and @jenncarneiro ) identified 3 flows contained in the Snowfakery Recipe Templates cumulusci.yml file. https://github.com/SFDO-Community-Sprints/Snowfakery-Recipe-Templates/blob/main/cumulusci.yml . Pretty sure these are the

1. osc_memberships_project. description: OSC Membership Schema and Benefits project
2. npsp_org. (no description)
3. npsp_scratch. description: Requires default org to be set. Installs npsp and creates a bunch of default settings to make the data look more realistic

• What would be a reasonable naming convention?
• Should we invent a prefix for our project and rename them with that?
• Will it actually help to rename them, or is this more of a "help contributors understand that custom cci flows only work in this repo".

Hey @prescod and/or @acrosman can you provide us some direction here?

[programmer2coder]

In a Zoom discussion with @prescod he agreed that an appropriate resolution to this issue would be to provide documentation to "help contributors understand that custom cci flows only work in this repo". And that no re-naming of the flows in the projects's cumulusci.yml file would be necessary.