cleanup: Move em only utils code into em directory

More separation of code for improvement of repository maintainability.

Change-Id: I4e77b472355066483cf646cdcd29e7ed660294a3
Signed-off-by: Christopher Meis <christopher.meis@9elements.com>
diff --git a/meson.build b/meson.build
index 7466b6d..26e4d79 100644
--- a/meson.build
+++ b/meson.build
@@ -137,8 +137,9 @@
         executable(
             'test_entity_manager',
             'test/test_entity-manager.cpp',
-            'src/expression.cpp',
+            'src/entity_manager/expression.cpp',
             'src/utils.cpp',
+            'src/entity_manager/utils.cpp',
             cpp_args: test_boost_args,
             dependencies: [
                 boost,