server-del: perform full master removal in managed topology

This patch implements most of the del_master_managed() functionality as a part
of `server-del` command.

`server-del` nows performs these actions:
  * check topology connectivity
  * check that at least one CA/DNS server and DNSSec masters are left
    after removal
  * cleanup all LDAP entries/attributes exposing information about the master
  * cleanup master DNS records
  * remove master and service principals
  * remove master entry from LDAP
  * check that all segments pointing to the master were removed

  `server-del` now accepts the following options:
  * `--force`: force master removal even if it doesn't exist
  * `--ignore-topology-disconnect`: ignore errors arising from disconnected
    topology before and after master removal
  * `--ignore-last-of-role`: remove master even if it is last DNS server,
    and DNSSec key master. The last CA will *not* be removed regardless of
    this option.

https://fedorahosted.org/freeipa/ticket/5588

Reviewed-By: Martin Basti <mbasti@redhat.com>

API.txt

@@ -4164,9 +4164,12 @@ output: Output('result', type=[<type 'bool'>])
 output: Output('summary', type=[<type 'unicode'>, <type 'NoneType'>])
 output: PrimaryKey('value')
 command: server_del
-args: 1,2,3
+args: 1,5,3
 arg: Str('cn+', cli_name='name')
 option: Flag('continue', autofill=True, cli_name='continue', default=False)
+option: Flag('force?', autofill=True, default=False)
+option: Flag('ignore_last_of_role?', autofill=True, default=False)
+option: Flag('ignore_topology_disconnect?', autofill=True, default=False)
 option: Str('version?')
 output: Output('result', type=[<type 'dict'>])
 output: Output('summary', type=[<type 'unicode'>, <type 'NoneType'>])