command line tools to see, modify and test existing LDAP configurations

Registers following command line tools:

```
ldap
  ldap:set-config             modifies an LDAP configuration
  ldap:show-config            shows the LDAP configuration
  ldap:test-config            tests an LDAP configuration
```

Example usages (/wo output):

```
./occ ldap:set-config s02 ldapUserDisplayName displayname    # sets displayname on configuration "s02"
```

```
./occ ldap:show-config        # shows all configurations
./occ ldap:show-config ""     # shows the (by default) first configuration
./occ ldap:show-config s02    # shows the configuration with the id s02
```

```
./occ ldap:test-config s02    # tests the configuration like the button on Advanced tab in LDAP settings
```

Please review/test @PVince81 @icewind1991 or others thx