Make stack allocator selectable by templated constructor.

I am not sure if this is appropriate, but it works and is no focus of this project.
4 jobs from coninuation in 32 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #3597
build_cmake

00:17

 
  Test
failed #3598
run_tests

00:14

 
  Sanitizer
skipped #3600
run_address_sanitizer
skipped #3599
run_thread_sanitizer
 
Test run_tests
compilation terminated.
make[2]: *** [lib/pls/CMakeFiles/pls.dir/src/internal/base/tas_spin_lock.cpp.o] Error 1
lib/pls/CMakeFiles/pls.dir/build.make:62: recipe for target 'lib/pls/CMakeFiles/pls.dir/src/internal/base/tas_spin_lock.cpp.o' failed
make[1]: *** [lib/pls/CMakeFiles/pls.dir/all] Error 2
CMakeFiles/Makefile2:250: recipe for target 'lib/pls/CMakeFiles/pls.dir/all' failed
make: *** [all] Error 2
Makefile:140: recipe for target 'all' failed
./ci_scripts/run_tests.sh: line 9: ./bin/tests: No such file or directory
ERROR: Job failed: exit code 1