main-func: Reduce transitive includes

Let's move some logic from _DEFINE_MAIN_FUNCTION() and other places
in main-func.h into functions that we implement in main-func.c to
allow moving some included headers from the header to the .c file.

src/resolve/resolvectl.c

@@ -5,18 +5,21 @@
 #include <net/if.h>
 
 #include "sd-bus.h"
+#include "sd-daemon.h"
 #include "sd-json.h"
 #include "sd-netlink.h"
 #include "sd-varlink.h"
 
 #include "af-list.h"
 #include "alloc-util.h"
+#include "argv-util.h"
 #include "build.h"
 #include "bus-common-errors.h"
 #include "bus-error.h"
 #include "bus-locator.h"
 #include "bus-map-properties.h"
 #include "bus-message-util.h"
+#include "bus-util.h"
 #include "dns-domain.h"
 #include "errno-list.h"
 #include "escape.h"
@@ -31,6 +34,7 @@
 #include "pager.h"
 #include "parse-argument.h"
 #include "parse-util.h"
+#include "polkit-agent.h"
 #include "pretty-print.h"
 #include "process-util.h"
 #include "resolvconf-compat.h"