* Test composition simplification from last PR
* Policies use proper API model everywhere
* Expose policy provenance in API, miss some dep injection
* Complete injection
* fix args
* Tests for provenance value
* Extract test helpers so tests are very readable
* Single source adapter struct that was copied in 3 places
* Drop redundant test
* Resolve merge conflicts on changelog
* Refactor GET am config to be extensible
* Extract post config route
* Fix tests
* Remove temporary duplication
* Fix broken test due to layer shift
* Fix duplicated error message
* Properly return 400 on config rejection
* Revert weird half method extraction
* Move things to notifier package and avoid redundant interface
* Simplify documentation
* Split encryption service and depend on minimal abstractions
* Properly initialize things all the way up to the composition root
* Encryption -> Crypto
* Address misc feedback
* Missing docstring
* Few more simple polish improvements
* Unify on MultiOrgAlertmanager. Discover bug in existing test
* Fix rebase conflicts
* Misc feedback, renames, docs
* Access crypto hanging off MultiOrgAlertmanager rather than having a separate API to initialize
