refactor(db): move users and persons functions into separate files

internal/db/users.go

@@ -0,0 +1,16 @@
+package db
+
+import "context"
+
+func UserLogin(ctx context.Context, login, password string) (user_id string, err error) {
+	row := connPool.QueryRow(ctx, "SELECT id FROM users WHERE login=$1 AND password=crypt($2, password)", login, password)
+	err = row.Scan(&user_id)
+	return
+}
+
+func UserAuth(ctx context.Context, user_id string) (ok, editor bool) {
+	row := connPool.QueryRow(ctx, "SELECT editor FROM users WHERE id=$1", user_id)
+	err := row.Scan(&editor)
+	ok = (err == nil)
+	return
+}