add db models, refactor json models, add references in migrations

internal/foundry/models/json/modules/pf2e.go

@@ -0,0 +1,12 @@
+package modules
+
+type Pf2eModule struct {
+	settings Pf2eSettings
+}
+
+type Pf2eSettings struct {
+	showEffectPanel      bool
+	showCheckDialogs     bool
+	showDamageDialogs    bool
+	monochromeDarkvision bool
+}