Background
Right now, we have a couple of variables that need (or can) be configured for any given wiki running GrowthExperiments. We need to decide which configuration settings should be maintained on-wiki, and which should be maintained in the server configuration (ie. only by us).
Requirements
Have a decision about which config variables will be managed by communities on-wiki, and which will be managed by Growth-Team in the server configuration. Implementation is out of scope here, and will be carried out in the parent task.
List of configuration options
See https://docs.google.com/spreadsheets/d/1B-9KeLFlCfJ_nq9X5taegyrZ0IW1lSZOD2kl-GjBppg/edit#gid=0.
In addition to the "classic" config variables set in extension.json, there is GrowthExperiments-NewcomerTasks configuration, which is already on-wiki (cf. https://cs.wikipedia.org/wiki/MediaWiki:NewcomerTasks.json), and it should be kept on-wiki.