Split out pretty-print.c and move pager.c and main-func.h to shared/

This is high-level functionality, and fits better in shared/ (which is for
our executables), than in basic/ (which is also for libraries).

src/basic/terminal-util.h

@@ -154,15 +154,3 @@ int open_terminal_in_namespace(pid_t pid, const char *name, int mode);
 
 int vt_default_utf8(void);
 int vt_reset_keyboard(int fd);
-
-int terminal_urlify(const char *url, const char *text, char **ret);
-int terminal_urlify_path(const char *path, const char *text, char **ret);
-int terminal_urlify_man(const char *page, const char *section, char **ret);
-
-typedef enum CatFlags {
-        CAT_FLAGS_MAIN_FILE_OPTIONAL = 1 << 0,
-} CatFlags;
-
-int cat_files(const char *file, char **dropins, CatFlags flags);
-
-void print_separator(void);