feat: extract into remaining packages

There has been a cyclic dependency.
transaction
	-> treasure_chest
	-> transaction_recurring
	-> transaction

This has been temporarily solved by moving the GenerateTransactions
function into the transaction package. In the future, this function has
to be rewritten to use a proper Service insteas of direct DB access or
replaced with a different system entirely.

test/auth_test.go

@@ -5,7 +5,6 @@ import (
 	"spend-sparrow/internal/auth_types"
 	"spend-sparrow/internal/authentication"
 	"spend-sparrow/internal/core"
-	"spend-sparrow/internal/types"
 	"spend-sparrow/mocks"
 	"strings"
 	"testing"
@@ -18,7 +17,7 @@ import (
 )
 
 var (
-	settings = types.Settings{
+	settings = core.Settings{
 		Port:        "",
 		BaseUrl:     "",
 		Environment: "test",