Migrate from Catch to Doctest

This reduces the build times of the test suite by about two thirds in my
testing in another project.

Change-Id: I8a5da3aff0956796c718d13237d0620f48316029
Depends-on: https://gerrit.cesnet.cz/c/CzechLight/dependencies/+/1580
diff --git a/tests/utils.cpp b/tests/utils.cpp
index e24b0d5..a6a982b 100644
--- a/tests/utils.cpp
+++ b/tests/utils.cpp
@@ -6,7 +6,7 @@
  *
 */
 
-#include "trompeloeil_catch.h"
+#include "trompeloeil_doctest.h"
 #include "utils.hpp"
 
 TEST_CASE("utils")