add spack post-installation testing

This Merge Request:

• adds or fixes tests for most EBRAINS (top-level) Spack packages
• adapts gitlab CI and installation script to run tests at installation time

packages/apbs/package.py

@@ -57,6 +57,9 @@ class Apbs(CMakePackage):
         # add suite-sparse libs to path because tests can't find them
         env.prepend_path("LD_LIBRARY_PATH", self.spec['suite-sparse'].prefix.lib)
 
+    def setup_dependent_build_environment(self, env, dependent_spec):
+        self.setup_build_environment(env)
+
     @run_after('install')
     @on_package_attributes(run_tests=True)
     def install_test(self):