Move tests to relevant subprojects (#615)

- Moved test projects to the parent project they belong to
- Improved test stability/corectness
- Improved recursive directory deletion by safely ignoring current- and parent-directory entries.
- Update docs

Modules/app-module/tests/CMakeLists.txt

@@ -0,0 +1,19 @@
+project(AppModuleTests)
+
+enable_language(C CXX ASM)
+
+
+file(GLOB_RECURSE TEST_SOURCES CONFIGURE_DEPENDS ${PROJECT_SOURCE_DIR}/source/*.cpp)
+add_executable(AppModuleTests EXCLUDE_FROM_ALL ${TEST_SOURCES})
+
+target_include_directories(AppModuleTests PRIVATE ${DOCTESTINC})
+
+add_test(NAME AppModuleTests COMMAND AppModuleTests)
+
+target_link_libraries(AppModuleTests PUBLIC
+    TactilityKernel
+    app-module
+    service-module
+    platform-posix
+    freertos_kernel
+)