Acceptance tests to cover different config.php settings

[phil-davis]

There are lots of parameters that can be set in config.php

• look through the parameters as documented in config.sample.php and make a priority list of which ones seem most important/most likely to be used in real installs/most likely to have "real" effects on the API or webUI
• identify parameters that are likely to interact/overlap in their effects
• make a plan for producing acceptance tests to cover the identified priorities

[phil-davis]

@patrickjahns @individual-it @davitol
See issue #31342 for an example where changing a config parameter seems to break some behavior.