large refactor (break up ConfigManager), add more tests

docs/reference/matching.md

@@ -0,0 +1,17 @@
+# Matching
+This file describes the naming and matching scheme employed by `symconf`.
+
+```
+~/.config/symconf/
+├── app_registry.toml
+└── apps/
+    └── <app>/
+        ├── user/                      # user managed
+        │   └── none-none.<config-name>
+        ├── generated/                 # automatically populated
+        │   └── none-none.<config-name>
+        ├── templates/                 # config templates
+        │   └── none-none.template
+        └── call/                      # reload scripts
+            └── none-none.sh
+```