Large commit which restructures the local password storage API.

Large commit which restructures the local password storage API.
Currently the only backend which works is smbpasswd (tdb, LDAP, and NIS+)
are broken, but they were somewhat broken before. :)

The following functions implement the storage manipulation interface

/*The following definitions come from  passdb/pdb_smbpasswd.c  */

BOOL pdb_setsampwent (BOOL update);
void pdb_endsampwent (void);
SAM_ACCOUNT* pdb_getsampwent (void);
SAM_ACCOUNT* pdb_getsampwnam (char *username);
SAM_ACCOUNT* pdb_getsampwuid (uid_t uid);
SAM_ACCOUNT* pdb_getsampwrid (uint32 rid);
BOOL pdb_add_sam_account (SAM_ACCOUNT *sampass);
BOOL pdb_update_sam_account (SAM_ACCOUNT *sampass, BOOL override);
BOOL pdb_delete_sam_account (char* username);

There is also a host of pdb_set..() and pdb_get..() functions for
manipulating SAM_ACCOUNT struct members.  Note that the struct
passdb_ops {} has gone away.  Also notice that struct smb_passwd
(formally in smb.h) has been moved to passdb/pdb_smbpasswd.c
and is not accessed outisde of static internal functions in this
file.  All local password searches should make use of the the SAM_ACCOUNT
struct and the previously mentioned functions.

I'll write some documentation for this later.  The next step is to fix
the TDB passdb backend, then work on spliting the backends out into
share libraries, and finally get the LDAP backend going.

What works and may not:

	o domain logons from Win9x 	works
	o domain logons from WinNT 4	works
	o user and group enumeration
		as implemented by Tim	works
	o file and print access		works
	o changing password from
		Win9x & NT		ummm...i'll fix this tonight :)

If I broke anything else, just yell and I'll fix it.  I think it
should be fairly quite.

-- jerry