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/wait-a-bit-longer.cpp b/tests/wait-a-bit-longer.cpp
index 029e36f..8ec4f4b 100644
--- a/tests/wait-a-bit-longer.cpp
+++ b/tests/wait-a-bit-longer.cpp
@@ -1,4 +1,4 @@
-#include <catch2/catch.hpp>
+#include <doctest/doctest.h>
 #include <chrono>
 #include <thread>
 #include <trompeloeil.hpp>