Store share ACL information persistently

While working on I have also tested this ticket

Change in PR is to add a field to the cifs_share table in freenas-v1.db store the share ACL in it. There are middleware API calls to view, edit, and synchronize the stored share ACL with share_info.tdb. Once per hour the mtime of share_info.tdb is compared with the results of the last check. If it is different, then the stored ACL is synchronized with the changes. If middleware is used to set a share ACL, it is written to both share_info.tdb and to cifs_share entry->cifs_share_acl.

There is no GUI component to it at this point.

11.3 PR: https://github.com/freenas/freenas/pull/3206

This should be stored in the config file. Mitigation step is move system dataset off of boot device.

Samba has the global parameter <pre>state directory =</pre> In FreeBSD port it defaults to "/var/db/samba4"

The state directory contains the following:
<pre>group_mapping.tdb
share_info.tdb
account_policy.tdb
winbindd_cache.tdb
winbindd_idmap.tdb
registry.tdb</pre>

Regardless of where the system dataset is stored, the state directory should reside on the data pool so that we maintain consistent state on failover.

So relevant checks before setting <pre>state directory = pool/.smb_statedirectory</pre>
1) Is this HA system and active node?
2) Is system dataset on boot device? (if it's already on pool, then we're preserving state on failover).
3) Is pool decrypted?
4) Does state directory exist?
(a)If not, create and copy state info from /var/db/samba4 on boot device to it.
(b)If it does exist, copy contents of state dir to /var/db/samba4

If (1)-(4) true, then add smb4.conf param.

This does the following for us:

• Keep state information on failover

• Maintains three copies of state information (data pool and both boot pools).