Reorganize project structure and fix SQLite usage

internal/store/model.go

@@ -0,0 +1,23 @@
+package store
+
+import "time"
+
+type Cake struct {
+	Name   string
+	ID     int
+	Price  int
+	Amount int
+}
+
+type Order struct {
+	ID       int
+	Name     string
+	Surname  string
+	Phone    string
+	Location string
+	Date     time.Time
+	Accepted time.Time
+	Status   string
+	Paid     int // increments of 0.01
+	Cakes    []Cake
+}