reworked cmake, unfortunately a big one due to interdependence

- /mission is a library now, in preparation of unittests (which bring their own main)
- eive-simple is now only available in bsp=arm/q7s (but is still not compiling)
- watchdog and simple are their own executables, not configurations any more
- moved some q7s specific code into /bsp-q7s to flatten if-hierarchy in main CMakeLists.txt
- compiler and linker options are not globally applied to all targets
- linux is the default fsfw osal now, as current code does not compile on hosted

bsp_q7s/simple/simple.cpp

@@ -1,5 +1,7 @@
 #include "simple.h"
 
+#include "iostream"
+
 #include "q7sConfig.h"
 
 #if Q7S_SIMPLE_ADD_FILE_SYSTEM_TEST == 1
@@ -7,7 +9,7 @@
 #endif
 
 int simple::simple() {
-  cout << "-- Q7S Simple Application --" << endl;
+  std::cout << "-- Q7S Simple Application --" << std::endl;
 #if Q7S_SIMPLE_ADD_FILE_SYSTEM_TEST == 1
   { FileSystemTest fileSystemTest; }
 #endif