Create 'edit host action' (2):
- Take care of old DocumentRoot.
- Synchronous call of deleteHost.php
Create 'edit host' action (3):
- Put #txtLastName in a better place.
- Synchronous call of newHost.php
Create host edit action (4):
- Put calls to refresh_host_list() and #btnCancelHost:click
  outside new_host() and delete_host().
Rename txtLastName to txtOldServerName.
Create host edit action (5):
- OldDocumentRoot is unnecessary.
- Show info outside of new_host(), delete_host() and
  edit_host().
- Content of edit_host().