lib: Drop internal virXXXPtr typedefs

Historically, we declared pointer type to our types:

  typedef struct _virXXX virXXX;
  typedef virXXX *virXXXPtr;

But usefulness of such declaration is questionable, at best.
Unfortunately, we can't drop every such declaration - we have to
carry some over, because they are part of public API (e.g.
virDomainPtr). But for internal types - we can do drop them and
use what every other C project uses 'virXXX *'.

This change was generated by a very ugly shell script that
generated sed script which was then called over each file in the
repository. For the shell script refer to the cover letter:

https://listman.redhat.com/archives/libvir-list/2021-March/msg00537.html

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>

docs/coding-style.rst

@@ -836,7 +836,7 @@ vircommand.h:
 
 ::
 
-  void virCommandAddEnvFormat(virCommandPtr cmd, const char *format, ...)
+  void virCommandAddEnvFormat(virCommand *cmd, const char *format, ...)
       G_GNUC_PRINTF(2, 3);
 
 This makes it so gcc's -Wformat and -Wformat-security options can