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.

internal/handler/middleware/cross_site_request_forgery.go

@@ -5,7 +5,6 @@ import (
 	"net/http"
 	"spend-sparrow/internal/authentication"
 	"spend-sparrow/internal/core"
-	"spend-sparrow/internal/utils"
 	"strings"
 )
 
@@ -52,7 +51,7 @@ func CrossSiteRequestForgery(auth authentication.Service) func(http.Handler) htt
 				if session == nil || csrfToken == "" || !auth.IsCsrfTokenValid(ctx, csrfToken, session.Id) {
 					slog.InfoContext(ctx, "CSRF-Token not correct", "token", csrfToken)
 					if r.Header.Get("Hx-Request") == "true" {
-						utils.TriggerToastWithStatus(ctx, w, r, "error", "CSRF-Token not correct", http.StatusBadRequest)
+						core.TriggerToastWithStatus(ctx, w, r, "error", "CSRF-Token not correct", http.StatusBadRequest)
 					} else {
 						http.Error(w, "CSRF-Token not correct", http.StatusBadRequest)
 					}
@@ -63,7 +62,7 @@ func CrossSiteRequestForgery(auth authentication.Service) func(http.Handler) htt
 			token, err := auth.GetCsrfToken(ctx, session)
 			if err != nil {
 				if r.Header.Get("Hx-Request") == "true" {
-					utils.TriggerToastWithStatus(ctx, w, r, "error", "Could not generate CSRF Token", http.StatusBadRequest)
+					core.TriggerToastWithStatus(ctx, w, r, "error", "Could not generate CSRF Token", http.StatusBadRequest)
 				} else {
 					http.Error(w, "Could not generate CSRF Token", http.StatusBadRequest)
 				}

internal/handler/middleware/security_headers.go

@@ -2,10 +2,10 @@ package middleware
 
 import (
 	"net/http"
-	"spend-sparrow/internal/types"
+	"spend-sparrow/internal/core"
 )
 
-func SecurityHeaders(serverSettings *types.Settings) func(http.Handler) http.Handler {
+func SecurityHeaders(serverSettings *core.Settings) func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			w.Header().Set("X-Content-Type-Options", "nosniff")